Topological data scripting/pt: Difference between revisions
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{{TutorialInfo/pt |
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|Topic=Programming |
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{{Docnav |
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|Level=Intermediate |
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|[[Part_scripting|Part scripting]] |
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|Time= |
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|[[Scripted_objects|Scripted objects]] |
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{{TOCright}} |
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==Introduction== |
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This page describes several methods for creating and modifying [[Part Module|Part shapes]] from python. Before reading this page, if you are new to python, it is a good idea to read about [[Introduction to Python|python scripting]] and [[FreeCAD Scripting Basics|how python scripting works in FreeCAD]]. |
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Here we will explain to you how to control the [[Part_Workbench|Part]] module directly from the FreeCAD Python interpreter, or from any external script. Be sure to browse the [[Scripting]] section and the [[FreeCAD_Scripting_Basics|FreeCAD Scripting Basics]] pages if you need more information about how Python scripting works in FreeCAD. If you are new to Python, it is a good idea to first read the [[Introduction_to_Python|Introduction to Python]]. |
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== Introduction == |
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We will here explain you how to control the [[Part Module]] directly from the FreeCAD python interpreter, or from any external script. The basics about Topological data scripting are described in [[Part_Module#Explaining_the_concepts|Part Module Explaining the concepts]]. Be sure to browse the [[Scripting]] section and the [[FreeCAD Scripting Basics]] pages if you need more information about how python scripting works in FreeCAD. |
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===See also=== |
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* [[Part_scripting|Part scripting]] |
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* [[OpenCASCADE|OpenCASCADE]] |
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==Class diagram== |
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=== Class Diagram === |
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This is a [http://en.wikipedia.org/wiki/Unified_Modeling_Language Unified Modeling Language (UML)] overview of the most important classes of the Part module: |
This is a [http://en.wikipedia.org/wiki/Unified_Modeling_Language Unified Modeling Language (UML)] overview of the most important classes of the Part module: |
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[[Image:Part_Classes.jpg |
[[Image:Part_Classes.jpg|Python classes of the Part module]] |
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{{Top}} |
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===Geometry=== |
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The geometric objects are the building blocks of all topological objects: |
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=== Geometry === |
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* '''Geom''' Base class of the geometric objects. |
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* '''Line''' A straight line in 3D, defined by starting point and end point. |
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* '''Geom''' Base class of the geometric objects |
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* ''' |
* '''Circle''' Circle or circle segment defined by a center point and start and end point. |
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* Etc. |
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* '''Circle''' Circle or circle segment defined by a center point and start and end point |
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{{Top}} |
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* '''......''' And soon some more |
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===Topology=== |
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=== Topology === |
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The following topological data types are available: |
The following topological data types are available: |
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* '''Compound''' A group of any type of topological |
* '''Compound''' A group of any type of topological objects. |
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* '''Compsolid''' A composite solid is a set of solids connected by their faces. It expands the notions of WIRE and SHELL to solids. |
* '''Compsolid''' A composite solid is a set of solids connected by their faces. It expands the notions of WIRE and SHELL to solids. |
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* '''Solid''' A part of space limited by shells. It is three dimensional. |
* '''Solid''' A part of space limited by shells. It is three dimensional. |
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Line 36: | Line 42: | ||
* '''Vertex''' A topological element corresponding to a point. It has zero dimension. |
* '''Vertex''' A topological element corresponding to a point. It has zero dimension. |
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* '''Shape''' A generic term covering all of the above. |
* '''Shape''' A generic term covering all of the above. |
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{{Top}} |
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== |
==Example: Create simple topology== |
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[[Image:Wire.png|Wire]] |
[[Image:Wire.png|Wire]] |
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We will now create a topology by constructing it out of simpler geometry. As a case study we will use a part as seen in the picture which consists of four vertices, two arcs and two lines. |
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{{Top}} |
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===Create geometry=== |
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First we create the distinct geometric parts of this wire. Making sure that parts that have to be connected later share the same vertices. |
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We will now create a topology by constructing it out of simpler geometry. |
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As a case study we use a part as seen in the picture which consists of |
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four vertexes, two circles and two lines. |
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So we create the points first: |
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==== Creating Geometry ==== |
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First we have to create the distinct geometric parts of this wire. |
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And we have to take care that the vertexes of the geometric parts |
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are at the '''same''' position. Otherwise later on we might not be |
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able to connect the geometric parts to a topology! |
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So we create first the points: |
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{{Code|code= |
{{Code|code= |
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import FreeCAD as App |
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import Part |
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V1 = Base.Vector(0,10,0) |
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V1 = App.Vector(0, 10, 0) |
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V2 = App.Vector(30, 10, 0) |
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V3 = App.Vector(30, -10, 0) |
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V4 = App.Vector(0, -10, 0) |
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}} |
}} |
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{{Top}} |
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=== |
===Arc=== |
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[[Image:Circel.png|Circle]] |
[[Image:Circel.png|Circle]] |
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For each arc we need a helper point: |
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circle through three points: |
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{{Code|code= |
{{Code|code= |
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VC1 = |
VC1 = App.Vector(-10, 0, 0) |
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C1 = Part.Arc(V1,VC1,V4) |
C1 = Part.Arc(V1, VC1, V4) |
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VC2 = App.Vector(40, 0, 0) |
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# and the second one |
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C2 = Part.Arc(V2, VC2, V3) |
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C2 = Part.Arc(V2,VC2,V3) |
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}} |
}} |
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{{Top}} |
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=== |
===Line=== |
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[[Image:Line.png|Line]] |
[[Image:Line.png|Line]] |
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The line can be created |
The line segments can be created from two points: |
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{{Code|code= |
{{Code|code= |
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L1 = Part. |
L1 = Part.LineSegment(V1, V2) |
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L2 = Part.LineSegment(V3, V4) |
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# and the second one |
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L2 = Part.Line(V4,V3) |
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}} |
}} |
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{{Top}} |
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===Put it all together=== |
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The last step is to put the geometric base elements together and bake a topological shape: |
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==== Putting all together ==== |
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The last step is to put the geometric base elements together |
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and bake a topological shape: |
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{{Code|code= |
{{Code|code= |
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S1 = Part.Shape([C1, |
S1 = Part.Shape([C1, L1, C2, L2]) |
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}} |
}} |
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{{Top}} |
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===Make a prism=== |
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==== Make a prism ==== |
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Now extrude the wire in a direction and make an actual 3D shape: |
Now extrude the wire in a direction and make an actual 3D shape: |
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{{Code|code= |
{{Code|code= |
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W = Part.Wire(S1.Edges) |
W = Part.Wire(S1.Edges) |
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P = W.extrude( |
P = W.extrude(App.Vector(0, 0, 10)) |
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}} |
}} |
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{{Top}} |
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=== |
===Show it all=== |
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{{Code|code= |
{{Code|code= |
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Part.show(P) |
Part.show(P) |
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}} |
}} |
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{{Top}} |
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==Create basic shapes== |
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You can easily create basic topological objects with the {{incode|make...()}} methods from the Part module: |
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== Creating basic shapes == |
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You can easily create basic topological objects with the "make...()" |
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methods from the Part Module: |
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{{Code|code= |
{{Code|code= |
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b = Part.makeBox(100,100,100) |
b = Part.makeBox(100, 100, 100) |
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Part.show(b) |
Part.show(b) |
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}} |
}} |
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Some available {{incode|make...()}} methods: |
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* |
* {{incode|makeBox(l, w, h, [p, d])}} Makes a box located in p and pointing into the direction d with the dimensions (l,w,h). |
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* |
* {{incode|makeCircle(radius)}} Makes a circle with a given radius. |
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* |
* {{incode|makeCone(radius1, radius2, height)}} Makes a cone with the given radii and height. |
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* |
* {{incode|makeCylinder(radius, height)}} Makes a cylinder with a given radius and height. |
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* |
* {{incode|makeLine((x1, y1, z1), (x2, y2, z2))}} Makes a line from two points. |
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* |
* {{incode|makePlane(length, width)}} Makes a plane with length and width. |
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* |
* {{incode|makePolygon(list)}} Makes a polygon from a list of points. |
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* |
* {{incode|makeSphere(radius)}} Makes a sphere with a given radius. |
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* |
* {{incode|makeTorus(radius1, radius2)}} Makes a torus with the given radii. |
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See the [[Part API]] page for a complete list of available methods of the Part module. |
See the [[Part_API|Part API]] page or this [https://freecad-python-stubs.readthedocs.io/en/latest/autoapi/Part/ autogenerated Python Part API documentation] for a complete list of available methods of the Part module. |
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{{Top}} |
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===Import modules=== |
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First we need to import the FreeCAD and Part modules so we can use their contents in Python: |
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==== Importing the needed modules ==== |
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First we need to import the Part module so we can use its contents in python. |
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We'll also import the Base module from inside the FreeCAD module: |
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{{Code|code= |
{{Code|code= |
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import FreeCAD as App |
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import Part |
import Part |
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from FreeCAD import Base |
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}} |
}} |
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{{Top}} |
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===Create a vector=== |
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[http://en.wikipedia.org/wiki/Euclidean_vector Vectors] are one of the most important pieces of information when building shapes. They usually contain three numbers (but not necessarily always): the X, Y and Z cartesian coordinates. You create a vector like this: |
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==== Creating a Vector ==== |
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[http://en.wikipedia.org/wiki/Euclidean_vector Vectors] are one of the most |
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important pieces of information when building shapes. They contain a 3 numbers |
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usually (but not necessarily always) the x, y and z cartesian coordinates. You |
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create a vector like this: |
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{{Code|code= |
{{Code|code= |
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myVector = |
myVector = App.Vector(3, 2, 0) |
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}} |
}} |
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We just created a vector at coordinates |
We just created a vector at coordinates X = 3, Y = 2, Z = 0. In the Part module, vectors are used everywhere. Part shapes also use another kind of point representation called Vertex which is simply a container for a vector. You access the vector of a vertex like this: |
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vectors are used everywhere. Part shapes also use another kind of point |
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representation, called Vertex, which is acually nothing else than a container |
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for a vector. You access the vector of a vertex like this: |
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{{Code|code= |
{{Code|code= |
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myVertex = myShape.Vertexes[0] |
myVertex = myShape.Vertexes[0] |
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print |
print(myVertex.Point) |
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> Vector (3, 2, 0) |
> Vector (3, 2, 0) |
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}} |
}} |
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{{Top}} |
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===Create an edge=== |
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An edge is nothing but a line with two vertices: |
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==== Creating an Edge ==== |
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An edge is nothing but a line with two vertexes: |
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{{Code|code= |
{{Code|code= |
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edge = Part.makeLine((0,0,0), (10,0,0)) |
edge = Part.makeLine((0, 0, 0), (10, 0, 0)) |
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edge.Vertexes |
edge.Vertexes |
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> [<Vertex object at 01877430>, <Vertex object at 014888E0>] |
> [<Vertex object at 01877430>, <Vertex object at 014888E0>] |
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Line 176: | Line 172: | ||
{{Code|code= |
{{Code|code= |
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vec1 = |
vec1 = App.Vector(0, 0, 0) |
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vec2 = |
vec2 = App.Vector(10, 0, 0) |
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line = Part. |
line = Part.LineSegment(vec1, vec2) |
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edge = line.toShape() |
edge = line.toShape() |
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}} |
}} |
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Line 190: | Line 186: | ||
> Vector (5, 0, 0) |
> Vector (5, 0, 0) |
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}} |
}} |
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{{Top}} |
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===Put the shape on screen=== |
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So far we created an edge object, but it doesn't appear anywhere on the screen. This is because the FreeCAD 3D scene only displays what you tell it to display. To do that, we use this simple |
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==== Putting the shape on screen ==== |
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So far we created an edge object, but it doesn't appear anywhere on screen. |
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This is because we just manipulated python objects here. The FreeCAD 3D scene |
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only displays what you tell it to display. To do that, we use this simple |
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method: |
method: |
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Line 201: | Line 196: | ||
}} |
}} |
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The show function creates an object in our FreeCAD document and assigns our "edge" shape to it. Use this whenever it is time to display your creation on screen. |
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{{Top}} |
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will be attributed to it. Use this whenever it's time to display your |
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===Create a wire=== |
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creation on screen. |
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A wire is a multi-edge line and can be created from a list of edges or even a list of wires: |
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==== Creating a Wire ==== |
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A wire is a multi-edge line and can be created from a list of edges |
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or even a list of wires: |
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{{Code|code= |
{{Code|code= |
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edge1 = Part.makeLine((0,0,0), (10,0,0)) |
edge1 = Part.makeLine((0, 0, 0), (10, 0, 0)) |
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edge2 = Part.makeLine((10,0,0), (10,10,0)) |
edge2 = Part.makeLine((10, 0, 0), (10, 10, 0)) |
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wire1 = Part.Wire([edge1,edge2]) |
wire1 = Part.Wire([edge1, edge2]) |
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edge3 = Part.makeLine((10,10,0), (0,10,0)) |
edge3 = Part.makeLine((10, 10, 0), (0, 10, 0)) |
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edge4 = Part.makeLine((0,10,0), (0,0,0)) |
edge4 = Part.makeLine((0, 10, 0), (0, 0, 0)) |
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wire2 = Part.Wire([edge3,edge4]) |
wire2 = Part.Wire([edge3, edge4]) |
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wire3 = Part.Wire([wire1,wire2]) |
wire3 = Part.Wire([wire1, wire2]) |
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wire3.Edges |
wire3.Edges |
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> [<Edge object at 016695F8>, <Edge object at 0197AED8>, <Edge object at 01828B20>, <Edge object at 0190A788>] |
> [<Edge object at 016695F8>, <Edge object at 0197AED8>, <Edge object at 01828B20>, <Edge object at 0190A788>] |
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Line 222: | Line 215: | ||
}} |
}} |
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Part.show(wire3) will display the 4 edges that compose our wire. Other |
{{incode|Part.show(wire3)}} will display the 4 edges that compose our wire. Other useful information can be easily retrieved: |
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useful information can be easily retrieved: |
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{{Code|code= |
{{Code|code= |
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Line 235: | Line 227: | ||
> False |
> False |
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}} |
}} |
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{{Top}} |
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===Create a face=== |
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Only faces created from closed wires will be valid. In this example, wire3 is a closed wire but wire2 is not (see above): |
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==== Creating a Face ==== |
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Only faces created from closed wires will be valid. In this example, wire3 |
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is a closed wire but wire2 is not a closed wire (see above) |
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{{Code|code= |
{{Code|code= |
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face = Part.Face(wire3) |
face = Part.Face(wire3) |
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face.Area |
face.Area |
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> 99. |
> 99.99999999999999 |
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face.CenterOfMass |
face.CenterOfMass |
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> Vector (5, 5, 0) |
> Vector (5, 5, 0) |
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Line 251: | Line 243: | ||
> True |
> True |
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sface = Part.Face(wire2) |
sface = Part.Face(wire2) |
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sface.isValid() |
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> False |
> False |
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}} |
}} |
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Only faces will have an area, |
Only faces will have an area, wires and edges do not. |
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{{Top}} |
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===Create a circle=== |
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A circle can be created like this: |
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==== Creating a Circle ==== |
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A circle can be created as simply as this: |
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{{Code|code= |
{{Code|code= |
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Line 266: | Line 259: | ||
}} |
}} |
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If you want to create it at certain position and with certain direction: |
If you want to create it at a certain position and with a certain direction: |
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{{Code|code= |
{{Code|code= |
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ccircle = Part.makeCircle(10, |
ccircle = Part.makeCircle(10, App.Vector(10, 0, 0), App.Vector(1, 0, 0)) |
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ccircle.Curve |
ccircle.Curve |
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> Circle (Radius : 10, Position : (10, 0, 0), Direction : (1, 0, 0)) |
> Circle (Radius : 10, Position : (10, 0, 0), Direction : (1, 0, 0)) |
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}} |
}} |
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ccircle will be created at distance 10 from |
ccircle will be created at distance 10 from the X origin and will be facing outwards along the X axis. Note: {{incode|makeCircle()}} only accepts {{incode|App.Vector()}} for the position and normal parameters, not tuples. You can also create part of the circle by giving a start and an end angle: |
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towards x axis. Note: makeCircle only accepts Base.Vector() for position |
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and normal but not tuples. You can also create part of the circle by giving |
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start angle and end angle as: |
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{{Code|code= |
{{Code|code= |
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from math import pi |
from math import pi |
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arc1 = Part.makeCircle(10, |
arc1 = Part.makeCircle(10, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 0, 180) |
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arc2 = Part.makeCircle(10, |
arc2 = Part.makeCircle(10, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 180, 360) |
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}} |
}} |
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Angles should be provided in degrees. If you have radians simply convert them using the formula: |
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Both arc1 and arc2 jointly will make a circle. Angles should be provided in |
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degrees |
{{incode|degrees <nowiki>=</nowiki> radians * 180/pi}} or by using Python's {{incode|math}} module: |
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degrees = radians * 180/PI or using python's math module (after doing import |
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math, of course): |
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{{Code|code= |
{{Code|code= |
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import math |
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degrees = math.degrees(radians) |
degrees = math.degrees(radians) |
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}} |
}} |
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{{Top}} |
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===Create an arc along points=== |
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Unfortunately there is no {{incode|makeArc()}} function, but we have the {{incode|Part.Arc()}} function to create an arc through three points. It creates an arc object joining the start point to the end point through the middle point. The arc object's {{incode|toShape()}} function must be called to get an edge object, the same as when using {{incode|Part.LineSegment}} instead of {{incode|Part.makeLine}}. |
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==== Creating an Arc along points ==== |
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Unfortunately there is no makeArc function but we have Part.Arc function to |
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create an arc along three points. Basically it can be supposed as an arc |
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joining start point and end point along the middle point. Part.Arc creates |
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an arc object on which .toShape() has to be called to get the edge object, |
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the same way as when using Part.Line instead of Part.makeLine. |
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{{Code|code= |
{{Code|code= |
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arc = Part.Arc( |
arc = Part.Arc(App.Vector(0, 0, 0), App.Vector(0, 5, 0), App.Vector(5, 5, 0)) |
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arc |
arc |
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> <Arc object> |
> <Arc object> |
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arc_edge = arc.toShape() |
arc_edge = arc.toShape() |
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Part.show(arc_edge) |
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}} |
}} |
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Arc only accepts |
{{incode|Arc()}} only accepts {{incode|App.Vector()}} for points and not tuples. You can also obtain an arc by using a portion of a circle: |
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we want which we can display using Part.show(arc_edge). You can also obtain |
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an arc by using a portion of a circle: |
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{{Code|code= |
{{Code|code= |
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from math import pi |
from math import pi |
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circle = Part.Circle( |
circle = Part.Circle(App.Vector(0, 0, 0), App.Vector(0, 0, 1), 10) |
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arc = Part.Arc( |
arc = Part.Arc(circle,0,pi) |
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}} |
}} |
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Arcs are valid edges |
Arcs are valid edges like lines, so they can be used in wires also. |
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{{Top}} |
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===Create a polygon=== |
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A polygon is simply a wire with multiple straight edges. The {{incode|makePolygon()}} function takes a list of points and creates a wire through those points: |
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==== Creating a polygon ==== |
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A polygon is simply a wire with multiple straight edges. The makePolygon |
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function takes a list of points and creates a wire along those points: |
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{{Code|code= |
{{Code|code= |
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lshape_wire = Part.makePolygon([ |
lshape_wire = Part.makePolygon([App.Vector(0, 5, 0), App.Vector(0, 0, 0), App.Vector(5, 0, 0)]) |
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}} |
}} |
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{{Top}} |
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===Create a Bézier curve=== |
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Bézier curves are used to model smooth curves using a series of poles (points) and optional weights. The function below makes a {{incode|Part.BezierCurve()}} from a series of {{incode|FreeCAD.Vector()}} points. Note: when "getting" and "setting" a single pole or weight, indices start at 1, not 0. |
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==== Creating a Bezier curve ==== |
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Bézier curves are used to model smooth curves using a series of poles (points) and optional weights. The function below makes a Part.BezierCurve from a series of FreeCAD.Vector points. (Note: when "getting" and "setting" a single pole or weight indices start at 1, not 0.) |
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{{Code|code= |
{{Code|code= |
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Line 338: | Line 324: | ||
return(edge) |
return(edge) |
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}} |
}} |
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{{Top}} |
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===Create a plane=== |
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A Plane is a flat rectangular surface. The method used to create one is {{incode|makePlane(length, width, [start_pnt, dir_normal])}}. By default start_pnt = Vector(0, 0, 0) and dir_normal = Vector(0, 0, 1). Using dir_normal = Vector(0, 0, 1) will create the plane facing in the positive Z axis direction, while dir_normal = Vector(1, 0, 0) will create the plane facing in the positive X axis direction: |
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==== Creating a Plane ==== |
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A Plane is simply a flat rectangular surface. The method used to create one is |
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this: '''makePlane(length,width,[start_pnt,dir_normal])'''. By default |
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start_pnt = Vector(0,0,0) and dir_normal = Vector(0,0,1). Using dir_normal = Vector(0,0,1) |
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will create the plane facing z axis, while dir_normal = Vector(1,0,0) will create the |
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plane facing x axis: |
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{{Code|code= |
{{Code|code= |
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plane = Part.makePlane(2,2) |
plane = Part.makePlane(2, 2) |
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plane |
plane |
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><Face object at 028AF990> |
> <Face object at 028AF990> |
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plane = Part.makePlane(2,2, |
plane = Part.makePlane(2, 2, App.Vector(3, 0, 0), App.Vector(0, 1, 0)) |
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plane.BoundBox |
plane.BoundBox |
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> BoundBox (3, 0, 0, 5, 0, 2) |
> BoundBox (3, 0, 0, 5, 0, 2) |
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}} |
}} |
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BoundBox is a cuboid enclosing the plane with a diagonal starting at |
{{incode|BoundBox}} is a cuboid enclosing the plane with a diagonal starting at (3, 0, 0) and ending at (5, 0, 2). Here the {{incode|BoundBox}} thickness along the Y axis is zero, since our shape is totally flat. |
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(3,0,0) and ending at (5,0,2). Here the BoundBox thickness in y axis is zero, |
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since our shape is totally flat. |
|||
Note: makePlane only accepts |
Note: {{incode|makePlane()}} only accepts {{incode|App.Vector()}} for start_pnt and dir_normal and not tuples. |
||
{{Top}} |
|||
===Create an ellipse=== |
|||
There are several ways to create an ellipse: |
|||
To create an ellipse there are several ways: |
|||
{{Code|code= |
{{Code|code= |
||
Line 368: | Line 350: | ||
}} |
}} |
||
Creates an ellipse with major radius 2 and minor radius 1 with the center |
Creates an ellipse with major radius 2 and minor radius 1 with the center at (0, 0, 0). |
||
{{Code|code= |
{{Code|code= |
||
Line 374: | Line 356: | ||
}} |
}} |
||
Creates a copy of the given ellipse. |
|||
{{Code|code= |
{{Code|code= |
||
Part.Ellipse(S1,S2,Center) |
Part.Ellipse(S1, S2, Center) |
||
}} |
}} |
||
Creates an ellipse centered on the point Center, where the plane of the |
Creates an ellipse centered on the point Center, where the plane of the ellipse is defined by Center, S1 and S2, its major axis is defined by Center and S1, its major radius is the distance between Center and S1, and its minor radius is the distance between S2 and the major axis. |
||
ellipse is defined by Center, S1 and S2, its major axis is defined by |
|||
Center and S1, its major radius is the distance between Center and S1, |
|||
and its minor radius is the distance between S2 and the major axis. |
|||
{{Code|code= |
{{Code|code= |
||
Part.Ellipse(Center,MajorRadius,MinorRadius) |
Part.Ellipse(Center, MajorRadius, MinorRadius) |
||
}} |
}} |
||
Creates an ellipse with major and minor radii MajorRadius and MinorRadius, |
Creates an ellipse with major and minor radii MajorRadius and MinorRadius, located in the plane defined by Center and the normal (0, 0, 1) |
||
and located in the plane defined by Center and the normal (0,0,1) |
|||
{{Code|code= |
{{Code|code= |
||
eli = Part.Ellipse( |
eli = Part.Ellipse(App.Vector(10, 0, 0), App.Vector(0, 5, 0), App.Vector(0, 0, 0)) |
||
Part.show(eli.toShape()) |
Part.show(eli.toShape()) |
||
}} |
}} |
||
In the above code we have passed S1, S2 and center. |
In the above code we have passed S1, S2 and center. Similar to {{incode|Arc}}, {{incode|Ellipse}} creates an ellipse object not an edge, so we need to convert it into an edge using {{incode|toShape()}} for display. |
||
Ellipse also creates an ellipse object but not edge, so we need to |
|||
convert it into edge using toShape() to display. |
|||
Note: |
Note: {{incode|Ellipse()}} only accepts {{incode|App.Vector()}} for points and not tuples. |
||
{{Code|code= |
{{Code|code= |
||
eli = Part.Ellipse( |
eli = Part.Ellipse(App.Vector(0, 0, 0), 10, 5) |
||
Part.show(eli.toShape()) |
Part.show(eli.toShape()) |
||
}} |
}} |
||
For the above Ellipse constructor we have passed center, MajorRadius and MinorRadius. |
|||
{{Top}} |
|||
===Create a torus=== |
|||
Using {{incode|makeTorus(radius1, radius2, [pnt, dir, angle1, angle2, angle])}}. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1), angle1 = 0, angle2 = 360 and angle = 360. Consider a torus as small circle sweeping along a big circle. Radius1 is the radius of the big circle, radius2 is the radius of the small circle, pnt is the center of the torus and dir is the normal direction. angle1 and angle2 are angles in degrees for the small circle; the last angle parameter is to make a section of the torus: |
|||
==== Creating a Torus ==== |
|||
Using the method '''makeTorus(radius1,radius2,[pnt,dir,angle1,angle2,angle])'''. By |
|||
default pnt=Vector(0,0,0),dir=Vector(0,0,1),angle1=0,angle2=360 and angle=360. |
|||
Consider a torus as small circle sweeping along a big circle. Radius1 is the |
|||
radius of big cirlce, radius2 is the radius of small circle, pnt is the center |
|||
of torus and dir is the normal direction. angle1 and angle2 are angles in |
|||
radians for the small circle, the last parameter angle is to make a section of |
|||
the torus: |
|||
{{Code|code= |
{{Code|code= |
||
Line 423: | Line 394: | ||
}} |
}} |
||
The above code will create a torus with diameter 20(radius 10) and thickness 4 |
The above code will create a torus with diameter 20 (radius 10) and thickness 4 (small circle radius 2) |
||
(small cirlce radius 2) |
|||
{{Code|code= |
{{Code|code= |
||
tor=Part.makeTorus(10,5, |
tor=Part.makeTorus(10, 5, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 0, 180) |
||
}} |
}} |
||
The above code will create a slice of the torus |
The above code will create a slice of the torus. |
||
{{Code|code= |
{{Code|code= |
||
tor=Part.makeTorus(10,5, |
tor=Part.makeTorus(10, 5, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 0, 360, 180) |
||
}} |
}} |
||
The above code will create a semi torus |
The above code will create a semi torus; only the last parameter is changed. i.e the remaining angles are defaults. Giving the angle 180 will create the torus from 0 to 180, that is, a half torus. |
||
{{Top}} |
|||
i.e the angle and remaining angles are defaults. Giving the angle 180 will |
|||
===Create a box or cuboid=== |
|||
create the torus from 0 to 180, that is, a half torus. |
|||
Using {{incode|makeBox(length, width, height, [pnt, dir])}}. |
|||
==== Creating a box or cuboid ==== |
|||
By default pnt = Vector(0, 0, 0) and dir = Vector(0, 0, 1). |
|||
Using '''makeBox(length,width,height,[pnt,dir])'''. |
|||
By default pnt=Vector(0,0,0) and dir=Vector(0,0,1) |
|||
{{Code|code= |
{{Code|code= |
||
box = Part.makeBox(10,10,10) |
box = Part.makeBox(10, 10, 10) |
||
len(box.Vertexes) |
len(box.Vertexes) |
||
> 8 |
> 8 |
||
}} |
}} |
||
{{Top}} |
|||
===Create a sphere=== |
|||
Using {{incode|makeSphere(radius, [pnt, dir, angle1, angle2, angle3])}}. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1), angle1 = -90, angle2 = 90 and angle3 = 360. Angle1 and angle2 are the vertical minimum and maximum of the sphere, angle3 is the sphere diameter. |
|||
==== Creating a Sphere ==== |
|||
Using '''makeSphere(radius,[pnt, dir, angle1,angle2,angle3])'''. By default |
|||
pnt=Vector(0,0,0), dir=Vector(0,0,1), angle1=-90, angle2=90 and angle3=360. |
|||
angle1 and angle2 are the vertical minimum and maximum of the sphere, angle3 |
|||
is the sphere diameter itself. |
|||
{{Code|code= |
{{Code|code= |
||
sphere = Part.makeSphere(10) |
sphere = Part.makeSphere(10) |
||
hemisphere = Part.makeSphere(10, |
hemisphere = Part.makeSphere(10, App.Vector(0, 0, 0), App.Vector(0, 0, 1), -90, 90, 180) |
||
}} |
}} |
||
{{Top}} |
|||
===Create a cylinder=== |
|||
Using {{incode|makeCylinder(radius, height, [pnt, dir, angle])}}. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1) and angle = 360. |
|||
==== Creating a Cylinder ==== |
|||
Using '''makeCylinder(radius,height,[pnt,dir,angle])'''. By default |
|||
pnt=Vector(0,0,0),dir=Vector(0,0,1) and angle=360 |
|||
<syntaxhighlight> |
|||
cylinder = Part.makeCylinder(5,20) |
|||
partCylinder = Part.makeCylinder(5,20,Base.Vector(20,0,0),Base.Vector(0,0,1),180) |
|||
</syntaxhighlight> |
|||
==== Creating a Cone ==== |
|||
Using '''makeCone(radius1,radius2,height,[pnt,dir,angle])'''. By default |
|||
pnt=Vector(0,0,0), dir=Vector(0,0,1) and angle=360 |
|||
<syntaxhighlight> |
|||
cone = Part.makeCone(10,0,20) |
|||
semicone = Part.makeCone(10,0,20,Base.Vector(20,0,0),Base.Vector(0,0,1),180) |
|||
</syntaxhighlight> |
|||
== Modifying shapes == |
|||
There are several ways to modify shapes. Some are simple transformation operations |
|||
such as moving or rotating shapes, other are more complex, such as unioning and |
|||
subtracting one shape from another. Be aware that |
|||
{{Code|code= |
|||
=== Transform operations === |
|||
cylinder = Part.makeCylinder(5, 20) |
|||
partCylinder = Part.makeCylinder(5, 20, App.Vector(20, 0, 0), App.Vector(0, 0, 1), 180) |
|||
}} |
|||
{{Top}} |
|||
===Create a cone=== |
|||
Using {{incode|makeCone(radius1, radius2, height, [pnt, dir, angle])}}. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1) and angle = 360. |
|||
==== Translating a shape ==== |
|||
Translating is the act of moving a shape from one place to another. |
|||
{{Code|code= |
|||
Any shape (edge, face, cube, etc...) can be translated the same way: |
|||
cone = Part.makeCone(10, 0, 20) |
|||
<syntaxhighlight> |
|||
semicone = Part.makeCone(10, 0, 20, App.Vector(20, 0, 0), App.Vector(0, 0, 1), 180) |
|||
myShape = Part.makeBox(2,2,2) |
|||
}} |
|||
myShape.translate(Base.Vector(2,0,0)) |
|||
{{Top}} |
|||
</syntaxhighlight> |
|||
==Modify shapes== |
|||
This will move our shape "myShape" 2 units in the x direction. |
|||
There are several ways to modify shapes. Some are simple transformation operations such as moving or rotating shapes, others are more complex, such as unioning and subtracting one shape from another. |
|||
{{Top}} |
|||
==Transform operations== |
|||
===Translate a shape=== |
|||
Translating is the act of moving a shape from one place to another. Any shape (edge, face, cube, etc...) can be translated the same way: |
|||
{{Code|code= |
|||
myShape = Part.makeBox(2, 2, 2) |
|||
myShape.translate(App.Vector(2, 0, 0)) |
|||
}} |
|||
This will move our shape "myShape" 2 units in the X direction. |
|||
{{Top}} |
|||
===Rotate a shape=== |
|||
To rotate a shape, you need to specify the rotation center, the axis, and the rotation angle: |
|||
{{Code|code= |
|||
myShape.rotate(App.Vector(0, 0, 0),App.Vector(0, 0, 1), 180) |
|||
}} |
|||
==== Rotating a shape ==== |
|||
To rotate a shape, you need to specify the rotation center, the axis, |
|||
and the rotation angle: |
|||
<syntaxhighlight> |
|||
myShape.rotate(Vector(0,0,0),Vector(0,0,1),180) |
|||
</syntaxhighlight> |
|||
The above code will rotate the shape 180 degrees around the Z Axis. |
The above code will rotate the shape 180 degrees around the Z Axis. |
||
{{Top}} |
|||
===Matrix transformations=== |
|||
A matrix is a very convenient way to store transformations in the 3D world. In a single matrix, you can set translation, rotation and scaling values to be applied to an object. For example: |
|||
==== Generic transformations with matrixes ==== |
|||
A matrix is a very convenient way to store transformations in the 3D |
|||
{{Code|code= |
|||
world. In a single matrix, you can set translation, rotation and scaling |
|||
myMat = App.Matrix() |
|||
values to be applied to an object. For example: |
|||
myMat.move(App.Vector(2, 0, 0)) |
|||
<syntaxhighlight> |
|||
myMat = Base.Matrix() |
|||
myMat.move(Base.Vector(2,0,0)) |
|||
myMat.rotateZ(math.pi/2) |
myMat.rotateZ(math.pi/2) |
||
}} |
|||
</syntaxhighlight> |
|||
Note: FreeCAD matrixes work in radians. Also, almost all matrix operations |
|||
that take a vector can also take |
Note: FreeCAD matrixes work in radians. Also, almost all matrix operations that take a vector can also take three numbers, so these two lines do the same thing: |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
myMat.move(2,0,0) |
|||
myMat.move |
myMat.move(2, 0, 0) |
||
myMat.move(App.Vector(2, 0, 0)) |
|||
</syntaxhighlight> |
|||
}} |
|||
When our matrix is set, we can apply it to our shape. FreeCAD provides 2 |
|||
methods to do that: transformShape() and transformGeometry(). The difference |
|||
is that with the first one, you are sure that no deformations will occur (see |
Once our matrix is set, we can apply it to our shape. FreeCAD provides two methods for doing that: {{incode|transformShape()}} and {{incode|transformGeometry()}}. The difference is that with the first one, you are sure that no deformations will occur (see [[#Scaling a shape|Scaling a shape]] below). We can apply our transformation like this: |
||
"scaling a shape" below). So we can apply our transformation like this: |
|||
{{Code|code= |
|||
<syntaxhighlight> |
|||
myShape.transformShape(myMat) |
|||
}} |
|||
</syntaxhighlight> |
|||
or |
or |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
myShape.transformGeometry(myMat) |
myShape.transformGeometry(myMat) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
==== Scaling a shape ==== |
|||
===Scale a shape=== |
|||
Scaling a shape is a more dangerous operation because, unlike translation |
|||
or rotation, scaling non-uniformly (with different values for x, y and z) |
|||
Scaling a shape is a more dangerous operation because, unlike translation or rotation, scaling non-uniformly (with different values for X, Y and Z) can modify the structure of the shape. For example, scaling a circle with a higher value horizontally than vertically will transform it into an ellipse, which behaves mathematically very differently. For scaling, we cannot use the {{incode|transformShape()}}, we must use {{incode|transformGeometry()}}: |
|||
can modify the structure of the shape. For example, scaling a circle with |
|||
a higher value horizontally than vertically will transform it into an |
|||
{{Code|code= |
|||
ellipse, which behaves mathematically very differenty. For scaling, we |
|||
myMat = App.Matrix() |
|||
can't use the transformShape, we must use transformGeometry(): |
|||
myMat.scale(2, 1, 1) |
|||
<syntaxhighlight> |
|||
myMat = Base.Matrix() |
|||
myMat.scale(2,1,1) |
|||
myShape=myShape.transformGeometry(myMat) |
myShape=myShape.transformGeometry(myMat) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
=== Boolean Operations === |
|||
==Boolean operations== |
|||
=== |
===Subtraction=== |
||
Subtracting a shape from another one is called "cut" in OCC/FreeCAD jargon |
|||
and is done like this: |
Subtracting a shape from another one is called "cut" in FreeCAD and is done like this: |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
cylinder = Part.makeCylinder(3,10,Base.Vector(0,0,0),Base.Vector(1,0,0)) |
|||
cylinder = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0)) |
|||
sphere = Part.makeSphere(5, App.Vector(5, 0, 0)) |
|||
diff = cylinder.cut(sphere) |
diff = cylinder.cut(sphere) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
==== Intersection ==== |
|||
===Intersection=== |
|||
The same way, the intersection between 2 shapes is called "common" and is done |
|||
this way: |
|||
The same way, the intersection between two shapes is called "common" and is done this way: |
|||
<syntaxhighlight> |
|||
cylinder1 = Part.makeCylinder(3,10,Base.Vector(0,0,0),Base.Vector(1,0,0)) |
|||
{{Code|code= |
|||
cylinder2 = Part.makeCylinder(3,10,Base.Vector(5,0,-5),Base.Vector(0,0,1)) |
|||
cylinder1 = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0)) |
|||
cylinder2 = Part.makeCylinder(3, 10, App.Vector(5, 0, -5), App.Vector(0, 0, 1)) |
|||
common = cylinder1.common(cylinder2) |
common = cylinder1.common(cylinder2) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
==== Union ==== |
|||
===Union=== |
|||
Union is called "fuse" and works the same way: |
Union is called "fuse" and works the same way: |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
cylinder1 = Part.makeCylinder(3,10,Base.Vector(0,0,0),Base.Vector(1,0,0)) |
|||
cylinder1 = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0)) |
|||
cylinder2 = Part.makeCylinder(3, 10, App.Vector(5, 0, -5), App.Vector(0, 0, 1)) |
|||
fuse = cylinder1.fuse(cylinder2) |
fuse = cylinder1.fuse(cylinder2) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
==== Section ==== |
|||
===Section=== |
|||
A Section is the intersection between a solid shape and a plane shape. |
|||
It will return an intersection curve, a compound with edges |
|||
A "section" is the intersection between a solid shape and a plane shape. It will return an intersection curve, a compound curve composed of edges. |
|||
<syntaxhighlight> |
|||
cylinder1 = Part.makeCylinder(3,10,Base.Vector(0,0,0),Base.Vector(1,0,0)) |
|||
{{Code|code= |
|||
cylinder2 = Part.makeCylinder(3,10,Base.Vector(5,0,-5),Base.Vector(0,0,1)) |
|||
cylinder1 = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0)) |
|||
cylinder2 = Part.makeCylinder(3, 10, App.Vector(5, 0, -5), App.Vector(0, 0, 1)) |
|||
section = cylinder1.section(cylinder2) |
section = cylinder1.section(cylinder2) |
||
section.Wires |
section.Wires |
||
Line 575: | Line 558: | ||
<Edge object at 0D86DE18>, <Edge object at 0D9B8E80>, <Edge object at 012A3640>, |
<Edge object at 0D86DE18>, <Edge object at 0D9B8E80>, <Edge object at 012A3640>, |
||
<Edge object at 0D8F4BB0>] |
<Edge object at 0D8F4BB0>] |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
==== Extrusion ==== |
|||
===Extrusion=== |
|||
Extrusion is the act of "pushing" a flat shape in a certain direction resulting in |
|||
a solid body. Think of a circle becoming a tube by "pushing it out": |
|||
Extrusion is the act of "pushing" a flat shape in a certain direction, resulting in a solid body. Think of a circle becoming a tube by "pushing it out": |
|||
<syntaxhighlight> |
|||
{{Code|code= |
|||
circle = Part.makeCircle(10) |
circle = Part.makeCircle(10) |
||
tube = circle.extrude( |
tube = circle.extrude(App.Vector(0, 0, 2)) |
||
}} |
|||
</syntaxhighlight> |
|||
If your circle is hollow, you will obtain a hollow tube. If your circle is actually |
|||
a disc |
If your circle is hollow, you will obtain a hollow tube. If your circle is actually a disc with a filled face, you will obtain a solid cylinder: |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
wire = Part.Wire(circle) |
wire = Part.Wire(circle) |
||
disc = Part.Face(wire) |
disc = Part.Face(wire) |
||
cylinder = disc.extrude( |
cylinder = disc.extrude(App.Vector(0, 0, 2)) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
== Exploring shapes == |
|||
==Explore shapes== |
|||
You can easily explore the topological data structure: |
You can easily explore the topological data structure: |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
import Part |
import Part |
||
b = Part.makeBox(100,100,100) |
b = Part.makeBox(100, 100, 100) |
||
b.Wires |
b.Wires |
||
w = b.Wires[0] |
w = b.Wires[0] |
||
Line 606: | Line 595: | ||
v = e.Vertexes[0] |
v = e.Vertexes[0] |
||
v.Point |
v.Point |
||
}} |
|||
</syntaxhighlight> |
|||
By typing the lines above in the python interpreter, you will gain a good |
|||
understanding of the structure of Part objects. Here, our makeBox() command |
|||
created a solid shape. This solid, like all Part solids, contains faces. |
|||
Faces always contain wires, which are lists of edges that border the face. |
|||
Each face has at least one closed wire (it can have more if the face has a hole). |
|||
In the wire, we can look at each edge separately, and inside each edge, we can |
|||
see the vertexes. Straight edges have only two vertexes, obviously. |
|||
By typing the lines above in the Python interpreter, you will gain a good understanding of the structure of Part objects. Here, our {{incode|makeBox()}} command created a solid shape. This solid, like all Part solids, contains faces. Faces always contain wires, which are lists of edges that border the face. Each face has at least one closed wire (it can have more if the face has a hole). In the wire, we can look at each edge separately, and inside each edge, we can see the vertices. Straight edges have only two vertices, obviously. |
|||
=== Edge analysis === |
|||
{{Top}} |
|||
In case of an edge, which is an arbitrary curve, it's most likely you want to |
|||
===Edge analysis=== |
|||
do a discretization. In FreeCAD the edges are parametrized by their lengths. |
|||
That means you can walk an edge/curve by its length: |
|||
In case of an edge, which is an arbitrary curve, it's most likely you want to do a discretization. In FreeCAD the edges are parametrized by their lengths. That means you can walk an edge/curve by its length: |
|||
<syntaxhighlight> |
|||
{{Code|code= |
|||
import Part |
import Part |
||
box = Part.makeBox(100,100,100) |
box = Part.makeBox(100, 100, 100) |
||
anEdge = box.Edges[0] |
anEdge = box.Edges[0] |
||
print |
print(anEdge.Length) |
||
}} |
|||
</syntaxhighlight> |
|||
Now you can access a lot of properties of the edge by using the length as a |
|||
position. That means if the edge is 100mm long the start position is 0 and |
Now you can access a lot of properties of the edge by using the length as a position. That means if the edge is 100mm long the start position is 0 and the end position 100. |
||
the end position 100. |
|||
{{Code|code= |
|||
<syntaxhighlight> |
|||
anEdge.tangentAt(0.0) # tangent direction at the beginning |
anEdge.tangentAt(0.0) # tangent direction at the beginning |
||
anEdge.valueAt(0.0) # Point at the beginning |
anEdge.valueAt(0.0) # Point at the beginning |
||
anEdge.valueAt(100.0) # Point at the end of the edge |
anEdge.valueAt(100.0) # Point at the end of the edge |
||
anEdge.derivative1At(50.0) # first derivative of the curve in the middle |
anEdge.derivative1At(50.0) # first derivative of the curve in the middle |
||
anEdge.derivative2At(50.0) # second derivative of the curve in the middle |
anEdge.derivative2At(50.0) # second derivative of the curve in the middle |
||
anEdge.derivative3At(50.0) # third derivative of the curve in the middle |
anEdge.derivative3At(50.0) # third derivative of the curve in the middle |
||
anEdge.centerOfCurvatureAt(50) # center of the curvature for that position |
anEdge.centerOfCurvatureAt(50) # center of the curvature for that position |
||
anEdge.curvatureAt(50.0) # the curvature |
anEdge.curvatureAt(50.0) # the curvature |
||
anEdge.normalAt(50) # normal vector at that position (if defined) |
anEdge.normalAt(50) # normal vector at that position (if defined) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
=== Using the selection === |
|||
===Use a selection=== |
|||
Here we see now how we can use the selection the user did in the viewer. |
|||
First of all we create a box and shows it in the viewer |
|||
Here we see now how we can use a selection the user did in the viewer. First of all we create a box and show it in the viewer. |
|||
<syntaxhighlight> |
|||
{{Code|code= |
|||
import Part |
import Part |
||
Part.show(Part.makeBox(100,100,100)) |
Part.show(Part.makeBox(100, 100, 100)) |
||
Gui.SendMsgToActiveView("ViewFit") |
Gui.SendMsgToActiveView("ViewFit") |
||
}} |
|||
</syntaxhighlight> |
|||
Select now some faces or edges. With this script you can |
|||
iterate all selected objects and their sub elements: |
Now select some faces or edges. With this script you can iterate over all selected objects and their sub elements: |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
for o in Gui.Selection.getSelectionEx(): |
for o in Gui.Selection.getSelectionEx(): |
||
print(o.ObjectName) |
|||
for s in o.SubElementNames: |
|||
print("name: ", s) |
|||
for s in o.SubObjects: |
|||
print("object: ", s) |
|||
}} |
|||
</syntaxhighlight> |
|||
Select some edges and this script will calculate the length: |
Select some edges and this script will calculate the length: |
||
<syntaxhighlight> |
|||
{{Code|code= |
|||
length = 0.0 |
length = 0.0 |
||
for o in Gui.Selection.getSelectionEx(): |
for o in Gui.Selection.getSelectionEx(): |
||
for s in o.SubObjects: |
|||
length += s.Length |
|||
print "Length of the selected edges:" ,length |
|||
print("Length of the selected edges: ", length) |
|||
</syntaxhighlight> |
|||
}} |
|||
== Complete example: The OCC bottle == |
|||
{{Top}} |
|||
A typical example found in the |
|||
==Example: The OCC bottle== |
|||
[http://www.opencascade.com/doc/occt-6.9.0/overview/html/occt__tutorial.html#sec1 OpenCasCade Technology Tutorial] |
|||
is how to build a bottle. This is a good exercise for FreeCAD too. In fact, |
|||
A typical example found on the [https://www.opencascade.com/doc/occt-6.9.0/overview/html/occt__tutorial.html OpenCasCade Technology website] is how to build a bottle. This is a good exercise for FreeCAD too. In fact, if you follow our example below and the OCC page simultaneously, you will see how well OCC structures are implemented in FreeCAD. The script is included in the FreeCAD installation (inside the {{FileName|Mod/Part}} folder) and can be called from the Python interpreter by typing: |
|||
you can follow our example below and the OCC page simultaneously, you will |
|||
understand well how OCC structures are implemented in FreeCAD. The complete script |
|||
{{Code|code= |
|||
below is also included in FreeCAD installation (inside the Mod/Part folder) and |
|||
can be called from the python interpreter by typing: |
|||
<syntaxhighlight> |
|||
import Part |
import Part |
||
import MakeBottle |
import MakeBottle |
||
bottle = MakeBottle.makeBottle() |
bottle = MakeBottle.makeBottle() |
||
Part.show(bottle) |
Part.show(bottle) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
=== The complete script === |
|||
===The script=== |
|||
Here is the complete MakeBottle script: |
|||
<syntaxhighlight> |
|||
import Part, FreeCAD, math |
|||
from FreeCAD import Base |
|||
def makeBottle(myWidth=50.0, myHeight=70.0, myThickness=30.0): |
|||
aPnt1=Base.Vector(-myWidth/2.,0,0) |
|||
aPnt2=Base.Vector(-myWidth/2.,-myThickness/4.,0) |
|||
aPnt3=Base.Vector(0,-myThickness/2.,0) |
|||
aPnt4=Base.Vector(myWidth/2.,-myThickness/4.,0) |
|||
aPnt5=Base.Vector(myWidth/2.,0,0) |
|||
aArcOfCircle = Part.Arc(aPnt2,aPnt3,aPnt4) |
|||
aSegment1=Part.Line(aPnt1,aPnt2) |
|||
aSegment2=Part.Line(aPnt4,aPnt5) |
|||
aEdge1=aSegment1.toShape() |
|||
aEdge2=aArcOfCircle.toShape() |
|||
aEdge3=aSegment2.toShape() |
|||
aWire=Part.Wire([aEdge1,aEdge2,aEdge3]) |
|||
aTrsf=Base.Matrix() |
|||
aTrsf.rotateZ(math.pi) # rotate around the z-axis |
|||
aMirroredWire=aWire.transformGeometry(aTrsf) |
|||
myWireProfile=Part.Wire([aWire,aMirroredWire]) |
|||
myFaceProfile=Part.Face(myWireProfile) |
|||
aPrismVec=Base.Vector(0,0,myHeight) |
|||
myBody=myFaceProfile.extrude(aPrismVec) |
|||
myBody=myBody.makeFillet(myThickness/12.0,myBody.Edges) |
|||
neckLocation=Base.Vector(0,0,myHeight) |
|||
neckNormal=Base.Vector(0,0,1) |
|||
myNeckRadius = myThickness / 4. |
|||
myNeckHeight = myHeight / 10 |
|||
myNeck = Part.makeCylinder(myNeckRadius,myNeckHeight,neckLocation,neckNormal) |
|||
myBody = myBody.fuse(myNeck) |
|||
faceToRemove = 0 |
|||
zMax = -1.0 |
|||
for xp in myBody.Faces: |
|||
try: |
|||
surf = xp.Surface |
|||
if type(surf) == Part.Plane: |
|||
z = surf.Position.z |
|||
if z > zMax: |
|||
zMax = z |
|||
faceToRemove = xp |
|||
except: |
|||
continue |
|||
myBody = myBody.makeThickness([faceToRemove],-myThickness/50 , 1.e-3) |
|||
return myBody |
|||
</syntaxhighlight> |
|||
=== Detailed explanation === |
|||
<syntaxhighlight> |
|||
import Part, FreeCAD, math |
|||
from FreeCAD import Base |
|||
</syntaxhighlight> |
|||
We will need,of course, the Part module, but also the FreeCAD.Base module, |
|||
which contains basic FreeCAD structures like vectors and matrixes. |
|||
<syntaxhighlight> |
|||
def makeBottle(myWidth=50.0, myHeight=70.0, myThickness=30.0): |
|||
aPnt1=Base.Vector(-myWidth/2.,0,0) |
|||
aPnt2=Base.Vector(-myWidth/2.,-myThickness/4.,0) |
|||
aPnt3=Base.Vector(0,-myThickness/2.,0) |
|||
aPnt4=Base.Vector(myWidth/2.,-myThickness/4.,0) |
|||
aPnt5=Base.Vector(myWidth/2.,0,0) |
|||
</syntaxhighlight> |
|||
Here we define our makeBottle function. This function can be called without |
|||
arguments, like we did above, in which case default values for width, height, |
|||
and thickness will be used. Then, we define a couple of points that will be used |
|||
for building our base profile. |
|||
<syntaxhighlight> |
|||
aArcOfCircle = Part.Arc(aPnt2,aPnt3,aPnt4) |
|||
aSegment1=Part.Line(aPnt1,aPnt2) |
|||
aSegment2=Part.Line(aPnt4,aPnt5) |
|||
</syntaxhighlight> |
|||
Here we actually define the geometry: an arc, made of 3 points, and two |
|||
line segments, made of 2 points. |
|||
<syntaxhighlight> |
|||
aEdge1=aSegment1.toShape() |
|||
aEdge2=aArcOfCircle.toShape() |
|||
aEdge3=aSegment2.toShape() |
|||
aWire=Part.Wire([aEdge1,aEdge2,aEdge3]) |
|||
</syntaxhighlight> |
|||
Remember the difference between geometry and shapes? Here we build |
|||
shapes out of our construction geometry. 3 edges (edges can be straight |
|||
or curved), then a wire made of those three edges. |
|||
<syntaxhighlight> |
|||
aTrsf=Base.Matrix() |
|||
aTrsf.rotateZ(math.pi) # rotate around the z-axis |
|||
aMirroredWire=aWire.transformGeometry(aTrsf) |
|||
myWireProfile=Part.Wire([aWire,aMirroredWire]) |
|||
</syntaxhighlight> |
|||
Until now we built only a half profile. Easier than building the whole profile |
|||
the same way, we can just mirror what we did, and glue both halfs together. |
|||
So we first create a matrix. A matrix is a very common way to apply transformations |
|||
to objects in the 3D world, since it can contain in one structure all basic |
|||
transformations that 3D objects can suffer (move, rotate and scale). Here, |
|||
after we create the matrix, we mirror it, and we create a copy of our wire |
|||
with that transformation matrix applied to it. We now have two wires, and |
|||
we can make a third wire out of them, since wires are actually lists of edges. |
|||
<syntaxhighlight> |
|||
myFaceProfile=Part.Face(myWireProfile) |
|||
aPrismVec=Base.Vector(0,0,myHeight) |
|||
myBody=myFaceProfile.extrude(aPrismVec) |
|||
myBody=myBody.makeFillet(myThickness/12.0,myBody.Edges) |
|||
</syntaxhighlight> |
|||
Now that we have a closed wire, it can be turned into a face. Once we have a face, |
|||
we can extrude it. Doing so, we actually made a solid. Then we apply a nice little |
|||
fillet to our object because we care about good design, don't we? |
|||
<syntaxhighlight> |
|||
neckLocation=Base.Vector(0,0,myHeight) |
|||
neckNormal=Base.Vector(0,0,1) |
|||
myNeckRadius = myThickness / 4. |
|||
myNeckHeight = myHeight / 10 |
|||
myNeck = Part.makeCylinder(myNeckRadius,myNeckHeight,neckLocation,neckNormal) |
|||
</syntaxhighlight> |
|||
Then, the body of our bottle is made, we still need to create a neck. So we |
|||
make a new solid, with a cylinder. |
|||
<syntaxhighlight> |
|||
myBody = myBody.fuse(myNeck) |
|||
</syntaxhighlight> |
|||
The fuse operation, which in other apps is sometimes called union, is very |
|||
powerful. It will take care of gluing what needs to be glued and remove parts that |
|||
need to be removed. |
|||
<syntaxhighlight> |
|||
return myBody |
|||
</syntaxhighlight> |
|||
Then, we return our Part solid as the result of our function. That Part solid, |
|||
like any other Part shape, can be attributed to an object in a FreeCAD document, with: |
|||
<syntaxhighlight> |
|||
myObject = FreeCAD.ActiveDocument.addObject("Part::Feature","myObject") |
|||
myObject.Shape = bottle |
|||
</syntaxhighlight> |
|||
or, more simple: |
|||
<syntaxhighlight> |
|||
Part.show(bottle) |
|||
</syntaxhighlight> |
|||
==Box pierced== |
|||
Here a complete example of building a box pierced. |
|||
For the purpose of this tutorial we will consider a reduced version of the script. In this version the bottle will not be hollowed out, and the neck of the bottle will not be threaded. |
|||
The construction is done side by side and when the cube is finished, it is hollowed out of a cylinder through. |
|||
<syntaxhighlight> |
|||
{{Code|code= |
|||
import Draft, Part, FreeCAD, math, PartGui, FreeCADGui, PyQt4 |
|||
import FreeCAD as App |
|||
import Part, math |
|||
from FreeCAD import Base |
|||
def makeBottleTut(myWidth = 50.0, myHeight = 70.0, myThickness = 30.0): |
|||
aPnt1=App.Vector(-myWidth / 2., 0, 0) |
|||
aPnt2=App.Vector(-myWidth / 2., -myThickness / 4., 0) |
|||
aPnt3=App.Vector(0, -myThickness / 2., 0) |
|||
aPnt4=App.Vector(myWidth / 2., -myThickness / 4., 0) |
|||
aPnt5=App.Vector(myWidth / 2., 0, 0) |
|||
aArcOfCircle = Part.Arc(aPnt2, aPnt3, aPnt4) |
|||
aSegment1=Part.LineSegment(aPnt1, aPnt2) |
|||
aSegment2=Part.LineSegment(aPnt4, aPnt5) |
|||
aEdge1=aSegment1.toShape() |
|||
aEdge2=aArcOfCircle.toShape() |
|||
aEdge3=aSegment2.toShape() |
|||
aWire=Part.Wire([aEdge1, aEdge2, aEdge3]) |
|||
aTrsf=App.Matrix() |
|||
aTrsf.rotateZ(math.pi) # rotate around the z-axis |
|||
aMirroredWire=aWire.copy() |
|||
aMirroredWire.transformShape(aTrsf) |
|||
myWireProfile=Part.Wire([aWire, aMirroredWire]) |
|||
myFaceProfile=Part.Face(myWireProfile) |
|||
aPrismVec=App.Vector(0, 0, myHeight) |
|||
myBody=myFaceProfile.extrude(aPrismVec) |
|||
myBody=myBody.makeFillet(myThickness / 12.0, myBody.Edges) |
|||
neckLocation=App.Vector(0, 0, myHeight) |
|||
neckNormal=App.Vector(0, 0, 1) |
|||
myNeckRadius = myThickness / 4. |
|||
myNeckHeight = myHeight / 10. |
|||
myNeck = Part.makeCylinder(myNeckRadius, myNeckHeight, neckLocation, neckNormal) |
|||
myBody = myBody.fuse(myNeck) |
|||
return myBody |
|||
el = makeBottleTut() |
|||
Part.show(el) |
|||
}} |
|||
{{Top}} |
|||
===Detailed explanation=== |
|||
{{Code|code= |
|||
import FreeCAD as App |
|||
import Part, math |
|||
}} |
|||
We will, of course, need the {{incode|FreeCAD}} and {{incode|Part}} modules. |
|||
{{Code|code= |
|||
def makeBottleTut(myWidth = 50.0, myHeight = 70.0, myThickness = 30.0): |
|||
aPnt1=App.Vector(-myWidth / 2., 0, 0) |
|||
aPnt2=App.Vector(-myWidth / 2., -myThickness / 4., 0) |
|||
aPnt3=App.Vector(0, -myThickness / 2., 0) |
|||
aPnt4=App.Vector(myWidth / 2., -myThickness / 4., 0) |
|||
aPnt5=App.Vector(myWidth / 2., 0, 0) |
|||
}} |
|||
Here we define our {{incode|makeBottleTut}} function. This function can be called without arguments, like we did above, in which case default values for width, height, and thickness will be used. Then, we define a couple of points that will be used for building our base profile. |
|||
{{Code|code= |
|||
... |
|||
aArcOfCircle = Part.Arc(aPnt2, aPnt3, aPnt4) |
|||
aSegment1=Part.LineSegment(aPnt1, aPnt2) |
|||
aSegment2=Part.LineSegment(aPnt4, aPnt5) |
|||
}} |
|||
Here we define the geometry: an arc, made of three points, and two line segments, made of two points. |
|||
{{Code|code= |
|||
... |
|||
aEdge1=aSegment1.toShape() |
|||
aEdge2=aArcOfCircle.toShape() |
|||
aEdge3=aSegment2.toShape() |
|||
aWire=Part.Wire([aEdge1, aEdge2, aEdge3]) |
|||
}} |
|||
Remember the difference between geometry and shapes? Here we build shapes out of our construction geometry. Three edges (edges can be straight or curved), then a wire made of those three edges. |
|||
{{Code|code= |
|||
... |
|||
aTrsf=App.Matrix() |
|||
aTrsf.rotateZ(math.pi) # rotate around the z-axis |
|||
aMirroredWire=aWire.copy() |
|||
aMirroredWire.transformShape(aTrsf) |
|||
myWireProfile=Part.Wire([aWire, aMirroredWire]) |
|||
}} |
|||
So far we have built only a half profile. Instead of building the whole profile the same way, we can just mirror what we did and glue both halves together. We first create a matrix. A matrix is a very common way to apply transformations to objects in the 3D world, since it can contain in one structure all basic transformations that 3D objects can undergo (move, rotate and scale). After we create the matrix we mirror it, then we create a copy of our wire and apply the transformation matrix to it. We now have two wires, and we can make a third wire out of them, since wires are actually lists of edges. |
|||
{{Code|code= |
|||
... |
|||
myFaceProfile=Part.Face(myWireProfile) |
|||
aPrismVec=App.Vector(0, 0, myHeight) |
|||
myBody=myFaceProfile.extrude(aPrismVec) |
|||
myBody=myBody.makeFillet(myThickness / 12.0, myBody.Edges) |
|||
}} |
|||
Now that we have a closed wire, it can be turned into a face. Once we have a face, we can extrude it. In doing so, we make a solid. Then we apply a nice little fillet to our object because we care about good design, don't we? |
|||
{{Code|code= |
|||
... |
|||
neckLocation=App.Vector(0, 0, myHeight) |
|||
neckNormal=App.Vector(0, 0, 1) |
|||
myNeckRadius = myThickness / 4. |
|||
myNeckHeight = myHeight / 10. |
|||
myNeck = Part.makeCylinder(myNeckRadius, myNeckHeight, neckLocation, neckNormal) |
|||
}} |
|||
At this point, the body of our bottle is made, but we still need to create a neck. So we make a new solid, with a cylinder. |
|||
{{Code|code= |
|||
... |
|||
myBody = myBody.fuse(myNeck) |
|||
}} |
|||
The fuse operation is very powerful. It will take care of gluing what needs to be glued and remove parts that need to be removed. |
|||
{{Code|code= |
|||
... |
|||
return myBody |
|||
}} |
|||
Then, we return our Part solid as the result of our function. |
|||
{{Code|code= |
|||
el = makeBottleTut() |
|||
Part.show(el) |
|||
}} |
|||
Finally, we call the function to actually create the part, then make it visible. |
|||
{{Top}} |
|||
==Example: Pierced box== |
|||
Here is a complete example of building a pierced box. |
|||
The construction is done one side at a time. When the cube is finished, it is hollowed out by cutting a cylinder through it. |
|||
{{Code|code= |
|||
import FreeCAD as App |
|||
import Part, math |
|||
size = 10 |
size = 10 |
||
poly = Part.makePolygon( |
poly = Part.makePolygon([(0, 0, 0), (size, 0, 0), (size, 0, size), (0, 0, size), (0, 0, 0)]) |
||
face1 = Part.Face(poly) |
face1 = Part.Face(poly) |
||
Line 839: | Line 833: | ||
face6 = Part.Face(poly) |
face6 = Part.Face(poly) |
||
myMat = |
myMat = App.Matrix() |
||
myMat.rotateZ(math.pi/2) |
|||
myMat.rotateZ(math.pi / 2) |
|||
face2.transformShape(myMat) |
face2.transformShape(myMat) |
||
face2.translate( |
face2.translate(App.Vector(size, 0, 0)) |
||
myMat.rotateZ(math.pi/2) |
myMat.rotateZ(math.pi / 2) |
||
face3.transformShape(myMat) |
face3.transformShape(myMat) |
||
face3.translate( |
face3.translate(App.Vector(size, size, 0)) |
||
myMat.rotateZ(math.pi/2) |
myMat.rotateZ(math.pi / 2) |
||
face4.transformShape(myMat) |
face4.transformShape(myMat) |
||
face4.translate( |
face4.translate(App.Vector(0, size, 0)) |
||
myMat = |
myMat = App.Matrix() |
||
myMat.rotateX(-math.pi/2) |
|||
myMat.rotateX(-math.pi / 2) |
|||
face5.transformShape(myMat) |
face5.transformShape(myMat) |
||
face6.transformShape(myMat) |
face6.transformShape(myMat) |
||
face6.translate( |
face6.translate(App.Vector(0, 0, size)) |
||
myShell = Part.makeShell([face1,face2,face3,face4,face5,face6]) |
|||
myShell = Part.makeShell([face1, face2, face3, face4, face5, face6]) |
|||
mySolid = Part.makeSolid(myShell) |
mySolid = Part.makeSolid(myShell) |
||
mySolidRev = mySolid.copy() |
|||
mySolidRev.reverse() |
|||
myCyl = Part.makeCylinder(2,20) |
myCyl = Part.makeCylinder(2, 20) |
||
myCyl.translate( |
myCyl.translate(App.Vector(size / 2, size / 2, 0)) |
||
cut_part = |
cut_part = mySolid.cut(myCyl) |
||
Part.show(cut_part) |
Part.show(cut_part) |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
== Loading and Saving == |
|||
==Loading and saving== |
|||
There are several ways to save your work in the Part module. You can |
|||
of course save your FreeCAD document, but you can also save Part |
|||
objects directly to common CAD formats, such as BREP, IGS, STEP and STL. |
|||
There are several ways to save your work. You can of course save your FreeCAD document, but you can also save [[Part_Workbench|Part]] objects directly to common CAD formats, such as BREP, IGS, STEP and STL. |
|||
Saving a shape to a file is easy. There are exportBrep(), exportIges(), |
|||
exportStl() and exportStep() methods availables for all shape objects. |
|||
Saving a shape to a file is easy. There are {{incode|exportBrep()}}, {{incode|exportIges()}}, {{incode|exportStep()}} and {{incode|exportStl()}} methods available for all shape objects. So, doing: |
|||
So, doing: |
|||
<syntaxhighlight> |
|||
{{Code|code= |
|||
import Part |
import Part |
||
s = Part.makeBox( |
s = Part.makeBox(10, 10, 10) |
||
s.exportStep("test.stp") |
s.exportStep("test.stp") |
||
}} |
|||
</syntaxhighlight> |
|||
this will save our box into a STEP file. To load a BREP, |
|||
will save our box into a STEP file. To load a BREP, IGES or STEP file: |
|||
<syntaxhighlight> |
|||
{{Code|code= |
|||
import Part |
import Part |
||
s = Part.Shape() |
s = Part.Shape() |
||
s.read("test.stp") |
s.read("test.stp") |
||
}} |
|||
</syntaxhighlight> |
|||
To convert an '''.stp''' in '''.igs''' file simply : |
|||
To convert a STEP file to an IGS file: |
|||
<syntaxhighlight> |
|||
{{Code|code= |
|||
import Part |
import Part |
||
s = Part.Shape() |
s = Part.Shape() |
||
s.read("file.stp") # incoming file igs, stp, stl, brep |
s.read("file.stp") # incoming file igs, stp, stl, brep |
||
s.exportIges("file.igs") # outbound file igs |
s.exportIges("file.igs") # outbound file igs |
||
}} |
|||
</syntaxhighlight> |
|||
{{Top}} |
|||
Note that importing or opening BREP, IGES or STEP files can also be done |
|||
directly from the File -> Open or File -> Import menu, while exporting |
|||
is with File -> Export |
|||
{{Docnav |
|||
{{docnav|Mesh Scripting|Mesh to Part}} |
|||
|[[Part_scripting|Part scripting]] |
|||
|[[Scripted_objects|Scripted objects]] |
|||
}} |
|||
{{Powerdocnavi{{#translation:}}}} |
|||
[[Category:Poweruser Documentation]] |
|||
[[Category: |
[[Category:Developer Documentation{{#translation:}}]] |
||
[[Category:Python Code{{#translation:}}]] |
|||
{{clear}} |
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Latest revision as of 18:55, 12 October 2023
Introduction
Here we will explain to you how to control the Part module directly from the FreeCAD Python interpreter, or from any external script. Be sure to browse the Scripting section and the FreeCAD Scripting Basics pages if you need more information about how Python scripting works in FreeCAD. If you are new to Python, it is a good idea to first read the Introduction to Python.
See also
Class diagram
This is a Unified Modeling Language (UML) overview of the most important classes of the Part module:
Geometry
The geometric objects are the building blocks of all topological objects:
- Geom Base class of the geometric objects.
- Line A straight line in 3D, defined by starting point and end point.
- Circle Circle or circle segment defined by a center point and start and end point.
- Etc.
Topology
The following topological data types are available:
- Compound A group of any type of topological objects.
- Compsolid A composite solid is a set of solids connected by their faces. It expands the notions of WIRE and SHELL to solids.
- Solid A part of space limited by shells. It is three dimensional.
- Shell A set of faces connected by their edges. A shell can be open or closed.
- Face In 2D it is part of a plane; in 3D it is part of a surface. Its geometry is constrained (trimmed) by contours. It is two dimensional.
- Wire A set of edges connected by their vertices. It can be an open or closed contour depending on whether the edges are linked or not.
- Edge A topological element corresponding to a restrained curve. An edge is generally limited by vertices. It has one dimension.
- Vertex A topological element corresponding to a point. It has zero dimension.
- Shape A generic term covering all of the above.
Example: Create simple topology
We will now create a topology by constructing it out of simpler geometry. As a case study we will use a part as seen in the picture which consists of four vertices, two arcs and two lines.
Create geometry
First we create the distinct geometric parts of this wire. Making sure that parts that have to be connected later share the same vertices.
So we create the points first:
import FreeCAD as App
import Part
V1 = App.Vector(0, 10, 0)
V2 = App.Vector(30, 10, 0)
V3 = App.Vector(30, -10, 0)
V4 = App.Vector(0, -10, 0)
Arc
For each arc we need a helper point:
VC1 = App.Vector(-10, 0, 0)
C1 = Part.Arc(V1, VC1, V4)
VC2 = App.Vector(40, 0, 0)
C2 = Part.Arc(V2, VC2, V3)
Line
The line segments can be created from two points:
L1 = Part.LineSegment(V1, V2)
L2 = Part.LineSegment(V3, V4)
Put it all together
The last step is to put the geometric base elements together and bake a topological shape:
S1 = Part.Shape([C1, L1, C2, L2])
Make a prism
Now extrude the wire in a direction and make an actual 3D shape:
W = Part.Wire(S1.Edges)
P = W.extrude(App.Vector(0, 0, 10))
Show it all
Part.show(P)
Create basic shapes
You can easily create basic topological objects with the make...()
methods from the Part module:
b = Part.makeBox(100, 100, 100)
Part.show(b)
Some available make...()
methods:
makeBox(l, w, h, [p, d])
Makes a box located in p and pointing into the direction d with the dimensions (l,w,h).makeCircle(radius)
Makes a circle with a given radius.makeCone(radius1, radius2, height)
Makes a cone with the given radii and height.makeCylinder(radius, height)
Makes a cylinder with a given radius and height.makeLine((x1, y1, z1), (x2, y2, z2))
Makes a line from two points.makePlane(length, width)
Makes a plane with length and width.makePolygon(list)
Makes a polygon from a list of points.makeSphere(radius)
Makes a sphere with a given radius.makeTorus(radius1, radius2)
Makes a torus with the given radii.
See the Part API page or this autogenerated Python Part API documentation for a complete list of available methods of the Part module.
Import modules
First we need to import the FreeCAD and Part modules so we can use their contents in Python:
import FreeCAD as App
import Part
Create a vector
Vectors are one of the most important pieces of information when building shapes. They usually contain three numbers (but not necessarily always): the X, Y and Z cartesian coordinates. You create a vector like this:
myVector = App.Vector(3, 2, 0)
We just created a vector at coordinates X = 3, Y = 2, Z = 0. In the Part module, vectors are used everywhere. Part shapes also use another kind of point representation called Vertex which is simply a container for a vector. You access the vector of a vertex like this:
myVertex = myShape.Vertexes[0]
print(myVertex.Point)
> Vector (3, 2, 0)
Create an edge
An edge is nothing but a line with two vertices:
edge = Part.makeLine((0, 0, 0), (10, 0, 0))
edge.Vertexes
> [<Vertex object at 01877430>, <Vertex object at 014888E0>]
Note: You can also create an edge by passing two vectors:
vec1 = App.Vector(0, 0, 0)
vec2 = App.Vector(10, 0, 0)
line = Part.LineSegment(vec1, vec2)
edge = line.toShape()
You can find the length and center of an edge like this:
edge.Length
> 10.0
edge.CenterOfMass
> Vector (5, 0, 0)
Put the shape on screen
So far we created an edge object, but it doesn't appear anywhere on the screen. This is because the FreeCAD 3D scene only displays what you tell it to display. To do that, we use this simple method:
Part.show(edge)
The show function creates an object in our FreeCAD document and assigns our "edge" shape to it. Use this whenever it is time to display your creation on screen.
Create a wire
A wire is a multi-edge line and can be created from a list of edges or even a list of wires:
edge1 = Part.makeLine((0, 0, 0), (10, 0, 0))
edge2 = Part.makeLine((10, 0, 0), (10, 10, 0))
wire1 = Part.Wire([edge1, edge2])
edge3 = Part.makeLine((10, 10, 0), (0, 10, 0))
edge4 = Part.makeLine((0, 10, 0), (0, 0, 0))
wire2 = Part.Wire([edge3, edge4])
wire3 = Part.Wire([wire1, wire2])
wire3.Edges
> [<Edge object at 016695F8>, <Edge object at 0197AED8>, <Edge object at 01828B20>, <Edge object at 0190A788>]
Part.show(wire3)
Part.show(wire3)
will display the 4 edges that compose our wire. Other useful information can be easily retrieved:
wire3.Length
> 40.0
wire3.CenterOfMass
> Vector (5, 5, 0)
wire3.isClosed()
> True
wire2.isClosed()
> False
Create a face
Only faces created from closed wires will be valid. In this example, wire3 is a closed wire but wire2 is not (see above):
face = Part.Face(wire3)
face.Area
> 99.99999999999999
face.CenterOfMass
> Vector (5, 5, 0)
face.Length
> 40.0
face.isValid()
> True
sface = Part.Face(wire2)
sface.isValid()
> False
Only faces will have an area, wires and edges do not.
Create a circle
A circle can be created like this:
circle = Part.makeCircle(10)
circle.Curve
> Circle (Radius : 10, Position : (0, 0, 0), Direction : (0, 0, 1))
If you want to create it at a certain position and with a certain direction:
ccircle = Part.makeCircle(10, App.Vector(10, 0, 0), App.Vector(1, 0, 0))
ccircle.Curve
> Circle (Radius : 10, Position : (10, 0, 0), Direction : (1, 0, 0))
ccircle will be created at distance 10 from the X origin and will be facing outwards along the X axis. Note: makeCircle()
only accepts App.Vector()
for the position and normal parameters, not tuples. You can also create part of the circle by giving a start and an end angle:
from math import pi
arc1 = Part.makeCircle(10, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 0, 180)
arc2 = Part.makeCircle(10, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 180, 360)
Angles should be provided in degrees. If you have radians simply convert them using the formula:
degrees = radians * 180/pi
or by using Python's math
module:
import math
degrees = math.degrees(radians)
Create an arc along points
Unfortunately there is no makeArc()
function, but we have the Part.Arc()
function to create an arc through three points. It creates an arc object joining the start point to the end point through the middle point. The arc object's toShape()
function must be called to get an edge object, the same as when using Part.LineSegment
instead of Part.makeLine
.
arc = Part.Arc(App.Vector(0, 0, 0), App.Vector(0, 5, 0), App.Vector(5, 5, 0))
arc
> <Arc object>
arc_edge = arc.toShape()
Part.show(arc_edge)
Arc()
only accepts App.Vector()
for points and not tuples. You can also obtain an arc by using a portion of a circle:
from math import pi
circle = Part.Circle(App.Vector(0, 0, 0), App.Vector(0, 0, 1), 10)
arc = Part.Arc(circle,0,pi)
Arcs are valid edges like lines, so they can be used in wires also.
Create a polygon
A polygon is simply a wire with multiple straight edges. The makePolygon()
function takes a list of points and creates a wire through those points:
lshape_wire = Part.makePolygon([App.Vector(0, 5, 0), App.Vector(0, 0, 0), App.Vector(5, 0, 0)])
Create a Bézier curve
Bézier curves are used to model smooth curves using a series of poles (points) and optional weights. The function below makes a Part.BezierCurve()
from a series of FreeCAD.Vector()
points. Note: when "getting" and "setting" a single pole or weight, indices start at 1, not 0.
def makeBCurveEdge(Points):
geomCurve = Part.BezierCurve()
geomCurve.setPoles(Points)
edge = Part.Edge(geomCurve)
return(edge)
Create a plane
A Plane is a flat rectangular surface. The method used to create one is makePlane(length, width, [start_pnt, dir_normal])
. By default start_pnt = Vector(0, 0, 0) and dir_normal = Vector(0, 0, 1). Using dir_normal = Vector(0, 0, 1) will create the plane facing in the positive Z axis direction, while dir_normal = Vector(1, 0, 0) will create the plane facing in the positive X axis direction:
plane = Part.makePlane(2, 2)
plane
> <Face object at 028AF990>
plane = Part.makePlane(2, 2, App.Vector(3, 0, 0), App.Vector(0, 1, 0))
plane.BoundBox
> BoundBox (3, 0, 0, 5, 0, 2)
BoundBox
is a cuboid enclosing the plane with a diagonal starting at (3, 0, 0) and ending at (5, 0, 2). Here the BoundBox
thickness along the Y axis is zero, since our shape is totally flat.
Note: makePlane()
only accepts App.Vector()
for start_pnt and dir_normal and not tuples.
Create an ellipse
There are several ways to create an ellipse:
Part.Ellipse()
Creates an ellipse with major radius 2 and minor radius 1 with the center at (0, 0, 0).
Part.Ellipse(Ellipse)
Creates a copy of the given ellipse.
Part.Ellipse(S1, S2, Center)
Creates an ellipse centered on the point Center, where the plane of the ellipse is defined by Center, S1 and S2, its major axis is defined by Center and S1, its major radius is the distance between Center and S1, and its minor radius is the distance between S2 and the major axis.
Part.Ellipse(Center, MajorRadius, MinorRadius)
Creates an ellipse with major and minor radii MajorRadius and MinorRadius, located in the plane defined by Center and the normal (0, 0, 1)
eli = Part.Ellipse(App.Vector(10, 0, 0), App.Vector(0, 5, 0), App.Vector(0, 0, 0))
Part.show(eli.toShape())
In the above code we have passed S1, S2 and center. Similar to Arc
, Ellipse
creates an ellipse object not an edge, so we need to convert it into an edge using toShape()
for display.
Note: Ellipse()
only accepts App.Vector()
for points and not tuples.
eli = Part.Ellipse(App.Vector(0, 0, 0), 10, 5)
Part.show(eli.toShape())
For the above Ellipse constructor we have passed center, MajorRadius and MinorRadius.
Create a torus
Using makeTorus(radius1, radius2, [pnt, dir, angle1, angle2, angle])
. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1), angle1 = 0, angle2 = 360 and angle = 360. Consider a torus as small circle sweeping along a big circle. Radius1 is the radius of the big circle, radius2 is the radius of the small circle, pnt is the center of the torus and dir is the normal direction. angle1 and angle2 are angles in degrees for the small circle; the last angle parameter is to make a section of the torus:
torus = Part.makeTorus(10, 2)
The above code will create a torus with diameter 20 (radius 10) and thickness 4 (small circle radius 2)
tor=Part.makeTorus(10, 5, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 0, 180)
The above code will create a slice of the torus.
tor=Part.makeTorus(10, 5, App.Vector(0, 0, 0), App.Vector(0, 0, 1), 0, 360, 180)
The above code will create a semi torus; only the last parameter is changed. i.e the remaining angles are defaults. Giving the angle 180 will create the torus from 0 to 180, that is, a half torus.
Create a box or cuboid
Using makeBox(length, width, height, [pnt, dir])
.
By default pnt = Vector(0, 0, 0) and dir = Vector(0, 0, 1).
box = Part.makeBox(10, 10, 10)
len(box.Vertexes)
> 8
Create a sphere
Using makeSphere(radius, [pnt, dir, angle1, angle2, angle3])
. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1), angle1 = -90, angle2 = 90 and angle3 = 360. Angle1 and angle2 are the vertical minimum and maximum of the sphere, angle3 is the sphere diameter.
sphere = Part.makeSphere(10)
hemisphere = Part.makeSphere(10, App.Vector(0, 0, 0), App.Vector(0, 0, 1), -90, 90, 180)
Create a cylinder
Using makeCylinder(radius, height, [pnt, dir, angle])
. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1) and angle = 360.
cylinder = Part.makeCylinder(5, 20)
partCylinder = Part.makeCylinder(5, 20, App.Vector(20, 0, 0), App.Vector(0, 0, 1), 180)
Create a cone
Using makeCone(radius1, radius2, height, [pnt, dir, angle])
. By default pnt = Vector(0, 0, 0), dir = Vector(0, 0, 1) and angle = 360.
cone = Part.makeCone(10, 0, 20)
semicone = Part.makeCone(10, 0, 20, App.Vector(20, 0, 0), App.Vector(0, 0, 1), 180)
Modify shapes
There are several ways to modify shapes. Some are simple transformation operations such as moving or rotating shapes, others are more complex, such as unioning and subtracting one shape from another.
Transform operations
Translate a shape
Translating is the act of moving a shape from one place to another. Any shape (edge, face, cube, etc...) can be translated the same way:
myShape = Part.makeBox(2, 2, 2)
myShape.translate(App.Vector(2, 0, 0))
This will move our shape "myShape" 2 units in the X direction.
Rotate a shape
To rotate a shape, you need to specify the rotation center, the axis, and the rotation angle:
myShape.rotate(App.Vector(0, 0, 0),App.Vector(0, 0, 1), 180)
The above code will rotate the shape 180 degrees around the Z Axis.
Matrix transformations
A matrix is a very convenient way to store transformations in the 3D world. In a single matrix, you can set translation, rotation and scaling values to be applied to an object. For example:
myMat = App.Matrix()
myMat.move(App.Vector(2, 0, 0))
myMat.rotateZ(math.pi/2)
Note: FreeCAD matrixes work in radians. Also, almost all matrix operations that take a vector can also take three numbers, so these two lines do the same thing:
myMat.move(2, 0, 0)
myMat.move(App.Vector(2, 0, 0))
Once our matrix is set, we can apply it to our shape. FreeCAD provides two methods for doing that: transformShape()
and transformGeometry()
. The difference is that with the first one, you are sure that no deformations will occur (see Scaling a shape below). We can apply our transformation like this:
myShape.transformShape(myMat)
or
myShape.transformGeometry(myMat)
Scale a shape
Scaling a shape is a more dangerous operation because, unlike translation or rotation, scaling non-uniformly (with different values for X, Y and Z) can modify the structure of the shape. For example, scaling a circle with a higher value horizontally than vertically will transform it into an ellipse, which behaves mathematically very differently. For scaling, we cannot use the transformShape()
, we must use transformGeometry()
:
myMat = App.Matrix()
myMat.scale(2, 1, 1)
myShape=myShape.transformGeometry(myMat)
Boolean operations
Subtraction
Subtracting a shape from another one is called "cut" in FreeCAD and is done like this:
cylinder = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0))
sphere = Part.makeSphere(5, App.Vector(5, 0, 0))
diff = cylinder.cut(sphere)
Intersection
The same way, the intersection between two shapes is called "common" and is done this way:
cylinder1 = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0))
cylinder2 = Part.makeCylinder(3, 10, App.Vector(5, 0, -5), App.Vector(0, 0, 1))
common = cylinder1.common(cylinder2)
Union
Union is called "fuse" and works the same way:
cylinder1 = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0))
cylinder2 = Part.makeCylinder(3, 10, App.Vector(5, 0, -5), App.Vector(0, 0, 1))
fuse = cylinder1.fuse(cylinder2)
Section
A "section" is the intersection between a solid shape and a plane shape. It will return an intersection curve, a compound curve composed of edges.
cylinder1 = Part.makeCylinder(3, 10, App.Vector(0, 0, 0), App.Vector(1, 0, 0))
cylinder2 = Part.makeCylinder(3, 10, App.Vector(5, 0, -5), App.Vector(0, 0, 1))
section = cylinder1.section(cylinder2)
section.Wires
> []
section.Edges
> [<Edge object at 0D87CFE8>, <Edge object at 019564F8>, <Edge object at 0D998458>,
<Edge object at 0D86DE18>, <Edge object at 0D9B8E80>, <Edge object at 012A3640>,
<Edge object at 0D8F4BB0>]
Extrusion
Extrusion is the act of "pushing" a flat shape in a certain direction, resulting in a solid body. Think of a circle becoming a tube by "pushing it out":
circle = Part.makeCircle(10)
tube = circle.extrude(App.Vector(0, 0, 2))
If your circle is hollow, you will obtain a hollow tube. If your circle is actually a disc with a filled face, you will obtain a solid cylinder:
wire = Part.Wire(circle)
disc = Part.Face(wire)
cylinder = disc.extrude(App.Vector(0, 0, 2))
Explore shapes
You can easily explore the topological data structure:
import Part
b = Part.makeBox(100, 100, 100)
b.Wires
w = b.Wires[0]
w
w.Wires
w.Vertexes
Part.show(w)
w.Edges
e = w.Edges[0]
e.Vertexes
v = e.Vertexes[0]
v.Point
By typing the lines above in the Python interpreter, you will gain a good understanding of the structure of Part objects. Here, our makeBox()
command created a solid shape. This solid, like all Part solids, contains faces. Faces always contain wires, which are lists of edges that border the face. Each face has at least one closed wire (it can have more if the face has a hole). In the wire, we can look at each edge separately, and inside each edge, we can see the vertices. Straight edges have only two vertices, obviously.
Edge analysis
In case of an edge, which is an arbitrary curve, it's most likely you want to do a discretization. In FreeCAD the edges are parametrized by their lengths. That means you can walk an edge/curve by its length:
import Part
box = Part.makeBox(100, 100, 100)
anEdge = box.Edges[0]
print(anEdge.Length)
Now you can access a lot of properties of the edge by using the length as a position. That means if the edge is 100mm long the start position is 0 and the end position 100.
anEdge.tangentAt(0.0) # tangent direction at the beginning
anEdge.valueAt(0.0) # Point at the beginning
anEdge.valueAt(100.0) # Point at the end of the edge
anEdge.derivative1At(50.0) # first derivative of the curve in the middle
anEdge.derivative2At(50.0) # second derivative of the curve in the middle
anEdge.derivative3At(50.0) # third derivative of the curve in the middle
anEdge.centerOfCurvatureAt(50) # center of the curvature for that position
anEdge.curvatureAt(50.0) # the curvature
anEdge.normalAt(50) # normal vector at that position (if defined)
Use a selection
Here we see now how we can use a selection the user did in the viewer. First of all we create a box and show it in the viewer.
import Part
Part.show(Part.makeBox(100, 100, 100))
Gui.SendMsgToActiveView("ViewFit")
Now select some faces or edges. With this script you can iterate over all selected objects and their sub elements:
for o in Gui.Selection.getSelectionEx():
print(o.ObjectName)
for s in o.SubElementNames:
print("name: ", s)
for s in o.SubObjects:
print("object: ", s)
Select some edges and this script will calculate the length:
length = 0.0
for o in Gui.Selection.getSelectionEx():
for s in o.SubObjects:
length += s.Length
print("Length of the selected edges: ", length)
Example: The OCC bottle
A typical example found on the OpenCasCade Technology website is how to build a bottle. This is a good exercise for FreeCAD too. In fact, if you follow our example below and the OCC page simultaneously, you will see how well OCC structures are implemented in FreeCAD. The script is included in the FreeCAD installation (inside the Mod/Part folder) and can be called from the Python interpreter by typing:
import Part
import MakeBottle
bottle = MakeBottle.makeBottle()
Part.show(bottle)
The script
For the purpose of this tutorial we will consider a reduced version of the script. In this version the bottle will not be hollowed out, and the neck of the bottle will not be threaded.
import FreeCAD as App
import Part, math
def makeBottleTut(myWidth = 50.0, myHeight = 70.0, myThickness = 30.0):
aPnt1=App.Vector(-myWidth / 2., 0, 0)
aPnt2=App.Vector(-myWidth / 2., -myThickness / 4., 0)
aPnt3=App.Vector(0, -myThickness / 2., 0)
aPnt4=App.Vector(myWidth / 2., -myThickness / 4., 0)
aPnt5=App.Vector(myWidth / 2., 0, 0)
aArcOfCircle = Part.Arc(aPnt2, aPnt3, aPnt4)
aSegment1=Part.LineSegment(aPnt1, aPnt2)
aSegment2=Part.LineSegment(aPnt4, aPnt5)
aEdge1=aSegment1.toShape()
aEdge2=aArcOfCircle.toShape()
aEdge3=aSegment2.toShape()
aWire=Part.Wire([aEdge1, aEdge2, aEdge3])
aTrsf=App.Matrix()
aTrsf.rotateZ(math.pi) # rotate around the z-axis
aMirroredWire=aWire.copy()
aMirroredWire.transformShape(aTrsf)
myWireProfile=Part.Wire([aWire, aMirroredWire])
myFaceProfile=Part.Face(myWireProfile)
aPrismVec=App.Vector(0, 0, myHeight)
myBody=myFaceProfile.extrude(aPrismVec)
myBody=myBody.makeFillet(myThickness / 12.0, myBody.Edges)
neckLocation=App.Vector(0, 0, myHeight)
neckNormal=App.Vector(0, 0, 1)
myNeckRadius = myThickness / 4.
myNeckHeight = myHeight / 10.
myNeck = Part.makeCylinder(myNeckRadius, myNeckHeight, neckLocation, neckNormal)
myBody = myBody.fuse(myNeck)
return myBody
el = makeBottleTut()
Part.show(el)
Detailed explanation
import FreeCAD as App
import Part, math
We will, of course, need the FreeCAD
and Part
modules.
def makeBottleTut(myWidth = 50.0, myHeight = 70.0, myThickness = 30.0):
aPnt1=App.Vector(-myWidth / 2., 0, 0)
aPnt2=App.Vector(-myWidth / 2., -myThickness / 4., 0)
aPnt3=App.Vector(0, -myThickness / 2., 0)
aPnt4=App.Vector(myWidth / 2., -myThickness / 4., 0)
aPnt5=App.Vector(myWidth / 2., 0, 0)
Here we define our makeBottleTut
function. This function can be called without arguments, like we did above, in which case default values for width, height, and thickness will be used. Then, we define a couple of points that will be used for building our base profile.
...
aArcOfCircle = Part.Arc(aPnt2, aPnt3, aPnt4)
aSegment1=Part.LineSegment(aPnt1, aPnt2)
aSegment2=Part.LineSegment(aPnt4, aPnt5)
Here we define the geometry: an arc, made of three points, and two line segments, made of two points.
...
aEdge1=aSegment1.toShape()
aEdge2=aArcOfCircle.toShape()
aEdge3=aSegment2.toShape()
aWire=Part.Wire([aEdge1, aEdge2, aEdge3])
Remember the difference between geometry and shapes? Here we build shapes out of our construction geometry. Three edges (edges can be straight or curved), then a wire made of those three edges.
...
aTrsf=App.Matrix()
aTrsf.rotateZ(math.pi) # rotate around the z-axis
aMirroredWire=aWire.copy()
aMirroredWire.transformShape(aTrsf)
myWireProfile=Part.Wire([aWire, aMirroredWire])
So far we have built only a half profile. Instead of building the whole profile the same way, we can just mirror what we did and glue both halves together. We first create a matrix. A matrix is a very common way to apply transformations to objects in the 3D world, since it can contain in one structure all basic transformations that 3D objects can undergo (move, rotate and scale). After we create the matrix we mirror it, then we create a copy of our wire and apply the transformation matrix to it. We now have two wires, and we can make a third wire out of them, since wires are actually lists of edges.
...
myFaceProfile=Part.Face(myWireProfile)
aPrismVec=App.Vector(0, 0, myHeight)
myBody=myFaceProfile.extrude(aPrismVec)
myBody=myBody.makeFillet(myThickness / 12.0, myBody.Edges)
Now that we have a closed wire, it can be turned into a face. Once we have a face, we can extrude it. In doing so, we make a solid. Then we apply a nice little fillet to our object because we care about good design, don't we?
...
neckLocation=App.Vector(0, 0, myHeight)
neckNormal=App.Vector(0, 0, 1)
myNeckRadius = myThickness / 4.
myNeckHeight = myHeight / 10.
myNeck = Part.makeCylinder(myNeckRadius, myNeckHeight, neckLocation, neckNormal)
At this point, the body of our bottle is made, but we still need to create a neck. So we make a new solid, with a cylinder.
...
myBody = myBody.fuse(myNeck)
The fuse operation is very powerful. It will take care of gluing what needs to be glued and remove parts that need to be removed.
...
return myBody
Then, we return our Part solid as the result of our function.
el = makeBottleTut()
Part.show(el)
Finally, we call the function to actually create the part, then make it visible.
Example: Pierced box
Here is a complete example of building a pierced box.
The construction is done one side at a time. When the cube is finished, it is hollowed out by cutting a cylinder through it.
import FreeCAD as App
import Part, math
size = 10
poly = Part.makePolygon([(0, 0, 0), (size, 0, 0), (size, 0, size), (0, 0, size), (0, 0, 0)])
face1 = Part.Face(poly)
face2 = Part.Face(poly)
face3 = Part.Face(poly)
face4 = Part.Face(poly)
face5 = Part.Face(poly)
face6 = Part.Face(poly)
myMat = App.Matrix()
myMat.rotateZ(math.pi / 2)
face2.transformShape(myMat)
face2.translate(App.Vector(size, 0, 0))
myMat.rotateZ(math.pi / 2)
face3.transformShape(myMat)
face3.translate(App.Vector(size, size, 0))
myMat.rotateZ(math.pi / 2)
face4.transformShape(myMat)
face4.translate(App.Vector(0, size, 0))
myMat = App.Matrix()
myMat.rotateX(-math.pi / 2)
face5.transformShape(myMat)
face6.transformShape(myMat)
face6.translate(App.Vector(0, 0, size))
myShell = Part.makeShell([face1, face2, face3, face4, face5, face6])
mySolid = Part.makeSolid(myShell)
myCyl = Part.makeCylinder(2, 20)
myCyl.translate(App.Vector(size / 2, size / 2, 0))
cut_part = mySolid.cut(myCyl)
Part.show(cut_part)
Loading and saving
There are several ways to save your work. You can of course save your FreeCAD document, but you can also save Part objects directly to common CAD formats, such as BREP, IGS, STEP and STL.
Saving a shape to a file is easy. There are exportBrep()
, exportIges()
, exportStep()
and exportStl()
methods available for all shape objects. So, doing:
import Part
s = Part.makeBox(10, 10, 10)
s.exportStep("test.stp")
will save our box into a STEP file. To load a BREP, IGES or STEP file:
import Part
s = Part.Shape()
s.read("test.stp")
To convert a STEP file to an IGS file:
import Part
s = Part.Shape()
s.read("file.stp") # incoming file igs, stp, stl, brep
s.exportIges("file.igs") # outbound file igs
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