Hi Boatstalker - well, MoI writes the surface as what is called a "Type 144" IGES object, which is a trimmed surface.

I don't see anything in that dialog that jumps out at me that would fix the problem you're seeing.

Have you contacted Prosurf technical support? That would probably be your best bet as to why your DXF polygon mesh is not created properly, it appears to be a bug in Prosurf, but really they are the ones that can confirm that.

The underlying surface isn't something that you really "get rid of", because it is a normal part of a trimmed surface to have a full surface underneath it. But if you see trimmed away portions when you shouldn't then that is caused by a bug in something not processing the trim curves properly.

Did you try that 3DWin converter from here: http://www.tb-software.com/products_2.html - that should enable you to export a .3ds or .stl file ( or .obj if you set it to use triangles) from MoI and then convert it into a .dxf using 3DWin. Does that DXF file then work for your final target application?

- Michael