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
