PythonOCC Shear transform testing

shear-test.py

from OCC.BRepPrimAPI import *
from OCC.BRepBuilderAPI import *
from OCC.gp import *
from OCC import StlAPI
from OCC.Precision import *
from OCC.Utils.Topology import *
from OCC.TopoDS import *
from OCC.TopAbs import *
from OCC.BRepMesh import *
from OCC.BRep import *

from pprint import pprint

def vtxkey(vtx):
  return '%.2f_%.2f_%.2f'%(vtx[0], vtx[1], vtx[2])


def printMesh(shape):
  vtxmap = {}

  BRepMesh_Mesh(shape, Precision_Confusion()) # TODO precision
  faces_iterator = Topo(shape).faces()
  for F in faces_iterator:
    face_location = F.Location()
    facing = BRep_Tool_Triangulation(F,face_location).GetObject()
    tab = facing.Nodes()
    tri = facing.Triangles()

    for i in range(1,facing.NbTriangles()+1):
      trian = tri.Value(i)
      if F.Orientation() == TopAbs_REVERSED:
        index1, index3, index2 = trian.Get()
      else:
        index1, index2, index3 = trian.Get()
      P1 = tab.Value(index1).Transformed(face_location.Transformation())      
      P2 = tab.Value(index2).Transformed(face_location.Transformation())      
      P3 = tab.Value(index3).Transformed(face_location.Transformation())      

      c1 = P1.XYZ().Coord()
      c2 = P2.XYZ().Coord()
      c3 = P3.XYZ().Coord()

      if not vtxmap.has_key(vtxkey(c1)): vtxmap[vtxkey(c1)] = c1
      if not vtxmap.has_key(vtxkey(c2)): vtxmap[vtxkey(c2)] = c2
      if not vtxmap.has_key(vtxkey(c3)): vtxmap[vtxkey(c3)] = c3

  pprint(vtxmap.values())

def main():
  box = BRepPrimAPI_MakeBox(1,1,1)

  print 'Before Shear Transform'
  printMesh(box.Shape())

  xform = gp_Trsf()
  xform.SetValues(
    1, 0.5, 0, 0,
    0, 1, 0, 0,
    0, 0, 1, 0,
    Precision_Angular(), Precision_Confusion()
  );
  brep = BRepBuilderAPI_Transform(box.Shape(), xform, False)
  brep.Build()

  print 'After Shear Transform'
  printMesh(brep.Shape())

  #StlAPI.StlAPI_Write(brep.Shape(), 'shearbox2.stl')

if __name__ == '__main__':
  main()