Mesh Scripting
Introduction
To get access to the Mesh
module you have to import it first:
import Mesh
Creation
To create an empty mesh object just use the standard constructor:
mesh = Mesh.Mesh()
You can also create an object from a file:
mesh = Mesh.Mesh("D:/temp/Something.stl")
Or create it out of a set of triangles described by their corner points:
triangles = [
# triangle 1
[-0.5000, -0.5000, 0.0000], [0.5000, 0.5000, 0.0000], [-0.5000, 0.5000, 0.0000],
#triangle 2
[-0.5000, -0.5000, 0.0000], [0.5000, -0.5000, 0.0000], [0.5000, 0.5000, 0.0000],
]
meshObject = Mesh.Mesh(triangles)
Mesh.show(meshObject)
The Mesh-Kernel takes care of creating a topologically correct data structure by sorting coincident points and edges.
Modeling
To create regular geometries you can use the Python module BuildRegularGeoms
:
import BuildRegularGeoms
This module provides methods to define simple rotation bodies like spheres, ellipsoids, cylinders, toroids and cones. And it also has a method to create a simple cube. A toroid, for instance, can be created as follows:
t = BuildRegularGeoms.Toroid(8.0, 2.0, 50) # list with several thousands triangles
m = Mesh.Mesh(t)
Mesh.show(m)
The first two parameters define the radii of the toroid and the third parameter is a sub-sampling factor for how many triangles are created. The higher this value the smoother the mesh.
The Mesh
module also provides three Boolean methods: union()
, intersection()
and difference()
:
m1, m2 # are the input mesh objects
m3 = Mesh.Mesh(m1) # create a copy of m1
m3.unite(m2) # union of m1 and m2, the result is stored in m3
m4 = Mesh.Mesh(m1)
m4.intersect(m2) # intersection of m1 and m2
m5 = Mesh.Mesh(m1)
m5.difference(m2) # the difference of m1 and m2
m6 = Mesh.Mesh(m2)
m6.difference(m1) # the difference of m2 and m1, usually the result is different to m5
Here is an example that creates a pipe using the difference()
method:
import FreeCAD, Mesh, BuildRegularGeoms
cylA = Mesh.Mesh(BuildRegularGeoms.Cylinder(2.0, 10.0, True, 1.0, 36))
cylB = Mesh.Mesh(BuildRegularGeoms.Cylinder(1.0, 12.0, True, 1.0, 36))
cylB.Placement.Base = (FreeCAD.Vector(-1, 0, 0)) # move cylB to avoid co-planar faces
pipe = cylA
pipe = pipe.difference(cylB)
pipe.flipNormals() # somehow required
d = FreeCAD.ActiveDocument
d.addObject("Mesh::Feature", "Pipe").Mesh = pipe
d.recompute()
Exporting
You can even write a mesh to a python module:
import os
path = os.environ.get("APPDATA") + "/FreeCAD/Macro/SavedMesh.py"
m.write(path)
import SavedMesh
m2 = Mesh.Mesh(SavedMesh.faces)
Notes
An extensive, though hard to use, source of mesh related scripting are the unit test scripts of the Mesh
module.
In these unit tests literally all methods are called and all properties/attributes are tweaked.
So if you are bold enough, take a look at the Unit Test module.
See also: Mesh API.
- Miscellaneous: Import mesh, Export mesh, Create mesh from shape, Regular solid, Unwrap Mesh, Unwrap Face
- Modifying: Harmonize normals, Flip normals, Fill holes, Close hole, Add triangle, Remove components, Remove components by hand, Smooth, Refinement, Decimation, Scale
- Boolean: Union, Intersection, Difference
- Cutting: Cut mesh, Trim mesh, Trim mesh with a plane, Create section from mesh and plane, Cross-sections
- Components and segments: Merge, Split by components, Create mesh segments, Create mesh segments from best-fit surfaces
- FreeCAD scripting: Python, Introduction to Python, Python scripting tutorial, FreeCAD Scripting Basics
- Modules: Builtin modules, Units, Quantity
- Workbenches: Workbench creation, Gui Commands, Commands, Installing more workbenches
- Meshes and Parts: Mesh Scripting, Topological data scripting, Mesh to Part, PythonOCC
- Parametric objects: Scripted objects, Viewproviders (Custom icon in tree view)
- Scenegraph: Coin (Inventor) scenegraph, Pivy
- Graphical interface: Interface creation, Interface creation completely in Python (1, 2, 3, 4, 5), PySide, PySide examples beginner, intermediate, advanced
- Macros: Macros, How to install macros
- Embedding: Embedding FreeCAD, Embedding FreeCADGui
- Other: Expressions, Code snippets, Line drawing function, FreeCAD vector math library (deprecated)
- Hubs: User hub, Power users hub, Developer hub