Hi Thomas Thanks for your thorough reply! I am using Vista and the md0.1 release of PythonOCC. I have used scons before - how big an issue is it to build PythonOCC on Windows (I have various versions of Visual Studio available - .NET, 2005, 2008)?
Thanks again, Frank Conradie Rossland, BC, Canada Thomas Paviot wrote: > Hi Frank, > > I tested your script and have the same result. You point out a really > *serious* bug related to python/OpenCascade memory management > conflicts. In a sense, when you're 'outside' the function, the python > object points to an OCC object that was deleted when exiting the > function. I thought I fixed this behaviour, and that it was enough to > use a custom destructor only for OCC objects that inherits from > Standard_Transient. I was wrong, and this fix has to be extended to > *all* OCC objects. Thanks for the feedback, I'll tryo to do that this > week-end (should be a simple line removing in the SWIG_generator.py > script). > > Anyway, this discussion is far from your needs! If you cannot wait for > the fix to be commited, I have one solution: > > Just after the line 'mkface = > BRepBuilderAPI.BRepBuilderAPI_MakeFace(mkwire.Wire())', add the > following line: > mkface.thisown = False > (Tells python to *not* delete the object when exiting the function). > The result is then: > > f faceInsideFunction.IsNull: 0 > <OCC.TopoDS.TopoDS_Face; proxy of <Swig Object of type 'TopoDS_Face *' > at 0x00AE28C0> > > returnedFace.IsNull: 0 > <OCC.TopoDS.TopoDS_Face; proxy of <Swig Object of type 'TopoDS_Face *' > at 0x00ADFBC0> > > > Jelle and I had a long discussion about this topic (memory > management). Our conclusion is that this stuff *must* be completely > hidden to the end-user (since it's not pythonic at all) before another > pythonOCC version is released. Thanks so much for your report, Franck. > I know exactly what to do and it will be done before the end of the > week-end. I have however a bad news: the complete solution will have > to be rebuild from scratch since amost all SWIG files will be modified. > > Just a question: what is your OS? Which pythonOCC version do you use? > > Best Regards, > > Thomas > > Frank Conradie a écrit : >> I was hoping someone could explain the following odd wrapper >> behavior: if I build a TopoDS_Face inside a Python function, then >> return it from the function, the returned face seems to be >> different/invalid in the calling scope. >> Here is the output: >> >> faceInsideFunction.IsNull: 0 >> <OCC.TopoDS.TopoDS_Face; proxy of <Swig Object of type 'TopoDS_Face >> *' at 0x01BE4640> > >> >> returnedFace.IsNull: 1 >> <OCC.TopoDS.TopoDS_Face; proxy of <Swig Object of type 'TopoDS_Face >> *' at 0x01BDF7E0> > >> >> And here is the code that generated this output: >> >> from OCC import gp, BRepBuilderAPI, TopoDS >> >> def MakeFace(pts): >> gpnts = [gp.gp_Pnt(x,y,z) for x,y,z in pts] >> n = len(gpnts) >> gpnts.append(gpnts[0]) >> mkwire = BRepBuilderAPI.BRepBuilderAPI_MakeWire() >> for i in range(n): >> mkedge = BRepBuilderAPI.BRepBuilderAPI_MakeEdge(gpnts[i], >> gpnts[i+1]) >> mkwire.Add(mkedge.Edge()) >> mkface = BRepBuilderAPI.BRepBuilderAPI_MakeFace(mkwire.Wire()) >> f = mkface.Face() >> print 'faceInsideFunction.IsNull:', f.IsNull() >> print f >> return f >> >> def Test1(): >> y = 0.000 >> o = 0.000 >> d = 0.100 >> fpts = [ >> [o, y,o ], >> [o+d,y,o ], >> [o+d,y,o+d], >> [o, y,o+d], >> ] >> f1 = MakeFace(fpts) >> print >> print 'returnedFace.IsNull:', f1.IsNull() >> print f1 >> >> if __name__ == '__main__': >> Test1() >> >> Thanks for a great project! >> Frank Conradie >> Rossland, BC, Canada >> >> >> _______________________________________________ >> Pythonocc-users mailing list >> Pythonocc-users@gna.org >> https://mail.gna.org/listinfo/pythonocc-users >> >> > _______________________________________________ Pythonocc-users mailing list Pythonocc-users@gna.org https://mail.gna.org/listinfo/pythonocc-users
