Surface Filling
Surface Filling |
Menu location |
---|
Surface → Filling |
Workbenches |
Surface |
Default shortcut |
None |
Introduced in version |
0.17 |
See also |
None |
Description
Surface Filling creates a surface from a series of connected boundary edges. The surface can be further controlled by adding constraint edges, vertices and a support surface.
The base geometry can belong to 2D curves created with the Draft Workbench or the Sketcher Workbench, but can also belong to 3D solid objects such as those created with the Part Workbench or the PartDesign Workbench.
Example of a filled surface, delimited by four edges located in the XY plane; (left) only the four edges, and (right) one additional curve in space that defines the curvature of the surface
Usage
- Press the Filling button.
- The Boundaries task panel opens. See Options.
- Select two or more edges in the 3D view:
- There is no need to press the Add edge button in the Boundaries section at this time.
- For a 360° circular boundary two semicircular edges can be selected.
- A preview of the final shape will be shown once enough valid geometry has been selected.
- Optionally select a Support surface. See Example.
- Optionally select one or more Edge constraints.
- Optionally select one or more Vertex constraints.
- Press OK button.
Options
All selected geometry is use to control, constrain, the shape and curvature of the surface
- In the Boundaries section a support surface and boundary edges can specified:
- Press the Support surface button and select a face in the 3D view to add a support surface.
- Press the Add edge button once to start selecting boundary edges in the 3D view.
- There are several ways to deselect boundary edges:
- Press the Remove edge button once to start deselecting edges in the 3D view.
- Select an edge in the list and press Delete.
- Right-click an edge in the list and select Remove from the context menu.
- In the Edge constraints section non-boundary edges can be specified:
- The selection options are similar to those in the Boundaries section.
- In the Vertex constraints section non-boundary vertices can be specified:
- The selection options are similar to those in the Boundaries section.
- Press Esc or the Cancel button to abort the operation.
Example
The Support surface acts as an additional constraint for the surface. The following example will give you an idea how it works:
- In the Part Workbench create a cylinder and set its DataAngle to
180°
. - Switch to the Surface Workbench and press the Filling button.
- Select the two semi-circular edges and the two straight edges that connect them.
- The result matches the four boundary edges, but the inner shape is quite different from the cylindrical face.
- Edit the Surface object and for the Support surface select the cylindrical face.
- The modified shape matches the cylindrical face pretty well.
Limitations
The surface code from the internal OpenCASCADE modelling kernel is fragile, and cannot handle wrong input properly. The following situations may cause problems, and may crash the program, so they should be avoided:
- Adding DataBoundary Edges to that would result in several closed faces. In this case, those edges should be added as DataUnbound Edges to control the curvature only.
- Using parametric DataBoundary Edges (for example, Draft BSplines) that when recomputed fail to produce a closed boundary. That is, the edges to be used as DataBoundary Edges must always form a closed shape, even if their internal properties change.
Properties
A Surface Filling (Surface::Filling
class) is derived from the basic Part Feature (Part::Feature
class, through the Part::Spline
subclass), therefore it shares all the latter's properties.
In addition to the properties described in Part Feature, the Surface Filling has the following properties in the property editor.
Data
Filling
- DataBoundary Edges (
LinkSubList
): boundary edges; C0 is required for edges without a corresponding face. - DataBoundary Faces (
StringList
): - DataBoundary Order (
IntegerList
): order of constraint on boundary faces;0
,1
, and2
are possible. - DataUnbound Edges (
LinkSubList
): unbound constraint edges; C0 is required for edges without a corresponding face. - DataUnbound Faces (
StringList
): - DataUnbound Order (
IntegerList
): order of constraint on unbound faces;0
,1
, and2
are possible. - DataFree Faces (
LinkSubList
): free constraint on a face. - DataFree Order (
IntegerList
): order of constraint on free faces. - DataPoints (
LinkSubList
): constraint points on surface. - DataInitial Face (
LinkSub
): initial surface to use. - DataDegree (
Integer
): starting degree, it defaults to3
. - DataPoints On Curve (
Integer
): number of points on an edge for constraint. - DataIterations (
Integer
): number of iterations, it defaults to2
. - DataAnisotropy (
Bool
): it defaults tofalse
. - DataTolerance2d (
Float
): 2D tolerance, it defaults to0.0
. - DataTolerance3d (
Float
): 3D tolerance, it defaults to0.0
. - DataTol Angular (
Float
): G1 tolerance, it defaults to0.01
. - DataTol Curvature (
Float
): G2 tolerance, it defaults to0.10
. - DataMaximum Degree (
Integer
): maximum curve degree, it defaults to8
. - DataMaximum Segments (
Integer
): maximum number of segments, it defaults to9
.
View
Base
- ViewControl Points (
Bool
): it defaults tofalse
; if set totrue
, it will show an overlay with the control points of the surface.
Scripting
See also: FreeCAD Scripting Basics.
The Surface Filling tool can be used in macros and from the Python console by adding the Surface::Filling
object.
- The edges to be used to define the surface must be assigned as a LinkSubList to the
BoundaryEdges
property of the object. - Auxiliary edges and vertices must be assigned as a LinkSubLists to the
UnboundEdges
andPoints
properties of the object. - All objects with edges need to be computed before they can be used as input for the properties of the Filling object.
import FreeCAD as App
import Draft
doc = App.newDocument()
a = App.Vector(-20, -20, 0)
b = App.Vector(-18, 25, 0)
c = App.Vector(60, 26, 0)
d = App.Vector(33, -20, 0)
points1 = [a, App.Vector(-20, -8, 0), App.Vector(-17, 7, 0), b]
obj1 = Draft.make_bspline(points1)
points2 = [b, App.Vector(0, 25, 0), c]
obj2 = Draft.make_bspline(points2)
points3 = [c, App.Vector(37, 4, 0), d]
obj3 = Draft.make_bspline(points3)
points4 = [d, App.Vector(-2, -18, 0), a]
obj4 = Draft.make_bspline(points4)
doc.recompute()
surf = doc.addObject("Surface::Filling", "Surface")
surf.BoundaryEdges = [(obj1, "Edge1"),
(obj2, "Edge1"),
(obj3, "Edge1"),
(obj4, "Edge1")]
doc.recompute()
# ---------------------------------------------------------
points_spl = [App.Vector(-10, 0, 2),
App.Vector(4, 0, 7),
App.Vector(18, 0, -5),
App.Vector(25, 0, 0),
App.Vector(30, 0, 0)]
aux_edge = Draft.make_bspline(points_spl)
doc.recompute()
surf.UnboundEdges = [(aux_edge, "Edge1")]
doc.recompute()
# ---------------------------------------------------------
aux_v1 = Draft.make_line(App.Vector(-13, -12, 5),
App.Vector(-13, -12, -5))
aux_v2 = Draft.make_line(App.Vector(-3, 18, 5),
App.Vector(-3, 18, -5))
doc.recompute()
surf.Points = [(aux_v1, "Vertex2"),
(aux_v2, "Vertex1")]
doc.recompute()
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