A bit off-topic, but I'd like to suggest another question : why compute non-overlapping volume? It may be justified if you want to compute the volume of a cluster, but it is perhaps not relevant if you compute the porosity of a confined sphere packing.
Bruno Václav Šmilauer a écrit : > > (1) For tetrahedral elements, I wonder it might be good to use the > > polygon boolean operations (there are some example cases in CGAL, 3D > > boolean operations, Nef_3), but for spheres I don't have any idea > > You can check in trunk:extra/tetra/Tetra.cpp:226 etc, it is exact 4hedra > intersection code which returns the intersection as union of a number of > 4hedra (0, 1, or more); I used it a bit and I am reasonably sure that it > is correct... But the algo is by its nature slow. > > > > (2) I wonder if opengl has any embedded methods, since it supports > > selection the object... > > AFAIK core openGL just gives you ray corresponding to the click (i.e. > ray that is projected as the point you clicked on the screen) and you > have to find by yourself what objects it intersects. It is drawing lib, > not geometry lib. > > > (3) More complicated algorithms like ray tracing, etc, but those > > algorithms are beyond my area of knowledge. > > The reason I think of those methods, is the sampling method (grid > > method) is still an approximate method, while polygon boolean > > operation is an accurate method..., I might be too critical at this:) > > Approximate alogs are tricky in that you have to code also some > sufficient precision criterion. Otherwise you will have to hardcode very > fine grid resolution to be reasonable for all corner cases. > > Please keep me (us?) posted on what you find out about this. You could > make a page on wiki on that, too :-) > > Vaclav > > _______________________________________________ > Yade-users mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/yade-users > > > -- _______________ Chareyre Bruno Maitre de conference Institut National Polytechnique de Grenoble Laboratoire 3S (Soils Solids Structures) - bureau E145 BP 53 - 38041, Grenoble cedex 9 - France Tél : 33 4 56 52 86 21 Fax : 33 4 76 82 70 00 ________________ _______________________________________________ Yade-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/yade-users
