2011/1/4 Balint Balassa <balint.bala...@gmx.de> > Hi everyone, > > I'm relatively new to pythonOCC and I'm having a bit of a problem with my > code. It's really quite basic. I created a cylinder and extracted an edge, > which I made into a wire and a face, which in theory should not be a > problem. Unfortunately the face does not show up in the display window (see > the code below). I've tried the doxygen documentation, but didn't find > anything helpful. Is there any way to make a face from extracted edges? > Thank you very much for your help in advance. > > Regards, > Balint > > > > import OCC.TopoDS > from OCC.Utils.Topology import Topo > from OCC.TopTools import * > import math > > from OCC.Display.SimpleGui import * > display, start_display, add_menu, add_function_to_menu = init_display() > > shroudRadius = 3.0 > hubRadius = 1.0 > radius = 0.2 > epsilon = 1.0e-1 > > ## Creating circle and making cylinder: > centerCircle = OCC.gp.gp_Pnt(hubRadius-epsilon, 0, 0.5) > myAX2 = OCC.gp.gp_Ax2(centerCircle,OCC.gp.gp_Dir(1, 0, 0)) > circle = OCC.gp.gp_Circ(myAX2, radius) > > Edge2 = OCC.BRepBuilderAPI.BRepBuilderAPI_MakeEdge(circle, 0, > 2.0*math.pi).Edge() > ExistingWire = OCC.BRepBuilderAPI.BRepBuilderAPI_MakeWire(Edge2).Wire() > PrismFace = > OCC.BRepBuilderAPI.BRepBuilderAPI_MakeFace(ExistingWire).Shape() > > length = OCC.gp.gp_Vec(shroudRadius-hubRadius+2.0*epsilon, 0, 0) > > bladeSurface = OCC.BRepPrimAPI.BRepPrimAPI_MakePrism(PrismFace, > length).Shape() > bladeSurface = OCC.BRepPrimAPI.BRepPrimAPI_MakePrism(ExistingWire, > length).Shape() > #display.DisplayShape(bladeSurface) > topoBlade = OCC.Utils.Topology.Topo(bladeSurface) > topoBlade.number_of_shells() > bladeFace = topoBlade.faces().next() > > ## Getting the desired edge: > edges = [] > for edge in topoBlade.edges_from_face(bladeFace): > edge.Reverse() > edges.append(edge) > > ## Creating wire and face > edgeWire = OCC.BRepBuilderAPI.BRepBuilderAPI_MakeWire(edges[1]).Wire() > edgeFace = OCC.BRepBuilderAPI.BRepBuilderAPI_MakeFace(edgeWire).Shape() > display.DisplayShape(edgeFace) > start_display() >
Hi Balint, Jelle's fix works perfectly, and is quite more pythonic than your code, however you may know *why* the planar face is not displayed. So here is a code that reproduces the issue you reported: ####### from OCC.BRepPrimAPI import * from OCC.BRepBuilderAPI import * from OCC.Utils.Construct import * from OCC.gp import * import math from OCC.Display.SimpleGui import * display, start_display, add_menu, add_function_to_menu = init_display() ## Creating circle centerCircle = gp_Pnt(1, 0, 0.5) myAX2 = gp_Ax2(centerCircle,gp_Dir(1, 0, 0)) circle = gp_Circ(myAX2, 0.2) edge = BRepBuilderAPI_MakeEdge(circle, 0, 2.0*math.pi).Edge() wire = BRepBuilderAPI_MakeWire(edge).Wire() ## Creating cylinder from extrusion of wire extrusion_vector = gp_Vec(2., 0., 0.) cylinderSurface = BRepPrimAPI_MakePrism(wire, extrusion_vector).Shape() planeFace = BRepBuilderAPI_MakeFace(wire).Shape() display.DisplayShape(planeFace) display.DisplayShape(cylinderSurface) start_display() ############ You will notice that the 'planeFace' is not displayed. However, if you switch the cylinderSurface and planeFace lines as following: planeFace = BRepBuilderAPI_MakeFace(wire).Shape() cylinderSurface = BRepPrimAPI_MakePrism(wire, extrusion_vector).Shape() Then this time, both planarFace and cylindersSurface will be displayed! Weird, no? There are strange things happening here with C++ references and pointers. Jelle's make_prim function actually pass the 'True' Parameter to the BRepPrimAPI_MakePrism class. Here is a part of the OCC documentation related to the BRepAPI_MakePrism class: """ //! Builds the prism of base S and vector V. If C is true, <br> //! S is copied. If Canonize is true then generated surfaces <br> //! are attempted to be canonized in simple types <br> Standard_EXPORT BRepPrimAPI_MakePrism(const TopoDS_Shape& S,const gp_Vec& V,const Standard_Boolean Copy = Standard_False,const Standard_Boolean Canonize = Standard_True); """ Just passing the 'True' parameter to BRepPrimAPI_MakePrism then makes the __init__ method copy the S shape and build the prism from that function. It's enough to solve the references/pointers/shared objects issues. Then, here is my solution to fix your code : just move the line cylinderSurface = BRepPrimAPI_MakePrism(wire, extrusion_vector).Shape() to cylinderSurface = BRepPrimAPI_MakePrism(wire, extrusion_vector,True).Shape() Less pythonic than Jelle (how could it be *more* pythonic than Jelle ;) ?), but I hope you will deeply understand what happened. Thomas
_______________________________________________ Pythonocc-users mailing list Pythonocc-users@gna.org https://mail.gna.org/listinfo/pythonocc-users
