i don't know much about assimp.but i think i will have to go there some day. Is there any tutorial about assimp with d3d? If not , gl is fine
The 3D CAD tool 99 times out of 100 produces valid file(albit with there own tweak on some formats like DAE, wavefront object )
I know that. But how could a professional 3d software give wrong indices or vertices?
It is typical to see corrupted geometry when programming object importers / exporters. Winding order is the simplest of the problems to solve. Typically invalid output is result of triangles indexing wrong vertices.
By the way, vs2012 model view failed to load the obj exported by max. But it worked well with blender's.
The problem most likely exists in your parser code, It is also posible that the CAD tool has produced a edge case with the file.
I would recomend that you use a tool like Assimp to do the heavy lifting for you and you just process the data from it.
It's what i do, And it saves me from the hassle of different 3D formats as it handles a nice variety of them.
Hope that helps
This ought to get you started.
If you need more help just ask, Or if you want I could post the code I am currently using(but that will change after some time next month due to grabage output when using multiple objects but I am sure that has to do with how I am handling the vertices though... )