Mesh Scripting

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To get access to the Mesh module you have to import it first:

import Mesh


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)

The Mesh-Kernel takes care of creating a topologically correct data structure by sorting coincident points and edges.



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)

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



You can even write a mesh to a python module:

import os
path = os.environ.get("APPDATA") + "/FreeCAD/Macro/"
import SavedMesh
m2 = Mesh.Mesh(SavedMesh.faces)



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.