Fenics geometry building API is based on CGAL, it can import CAD, but can not export CAD file like step. Here is a solution, not fully tested. This file may be further developed in github.
#FreeCAD path
import sys
sys.path.append("/usr/lib/freecad/lib")
import FreeCAD
App = FreeCAD
import Part
FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Units/").SetInt("UserSchema", 1) # MKS ==0
# standard length should be in metre
# to be more compatible with Fenics mshr package
from FreeCAD import Vector as Point
def Box(p1, p2): # corners points
box = App.ActiveDocument.addObject("Part::Box", 'Box')
#new_center = (p2+p1).scale(0.5, 0.5, 0.5)
new_pos = p1 # assume each component of p2 > p1
box.Placement.move( new_pos )
dim = p2-p1
box.Length = math.fabs(dim[0])
box.Width = math.fabs(dim[1])
box.Height = math.fabs(dim[2])
return box
def Cylinder(p1, p2, r1, r2):
c = App.ActiveDocument.addObject("Part::Cylinder", 'Cylinder')
#new_center = (p2+p1).scale(0.5, 0.5, 0.5)
new_pos = p1 # assume each component of p2 > p1
scaler = 1.0/(p2-p1).Length
axis_vector = (p2-p1).scale(scaler, scaler, scaler)
c.Placement = App.Placement(new_pos, App.Rotation(axis_vector, 0)) # axis setting does not work
#c.Placement.move( new_pos )
#c.Placement.move( new_pos )
c.Height = (p2-p1).Length
c.Radius = r1
return c
def CSGUnion(base, tool):
out = App.activeDocument().addObject("Part::Fuse","Union")
out.Base = base
out.Tool = tool
return out
def CSGIntersection(base, tool):
out = App.activeDocument().addObject("Part::Common","Intersecton")
out.Base = base
out.Tool = tool
return out
def CSGDifference(base, tool):
out = App.activeDocument().addObject("Part::Cut","Cut")
out.Base = base
out.Tool = tool
return out
##################################################
def test():
box1 = Box(Point(0, 0, 0), Point(10, 20, 30))
cylinder = Cylinder(Point(10, 0, 25), Point(20, 0, 25), 5, 5)
box2 = Box(Point(05, 15, 25), Point(15, 25, 35))
box = CSGUnion(box1, box2)
return CSGUnion(box, cylinder)
def export_geom(docname):
App.newDocument(docname)
App.setActiveDocument(docname)
App.ActiveDocument=App.getDocument(docname)
goem = test()
App.ActiveDocument.recompute()
__objs__ = []
__objs__.append( goem )
Part.export(__objs__,"{}.step".format(docname))
App.ActiveDocument.saveAs("/tmp/{}.fcstd".format(docname))
def main():
export_geom("myGeom")
if __name__ == '__main__':
main()
CC-BY-NC 4.0 licensed free for non-commercial usage
Author: Qingfeng XIA
copyright (C) 2011-2020
http://www.iesensor.com
please keep the original link in your reference.
http://www.iesensor.com/blog/2017/02/27/freecad-compatible-fenics-mshr-geometry-building/
