Export to Google Sketchup works fine with the gobetween Blender Obj -->dxf :)
(3DS don't want work in Google Sketchup ??? with the Canon file of Steph :(
Here my try with only less triangles (other Ngones or Quads + trianles don't well works for Google Sketchup)

Ps During the export in MoI does it possible to see somewhere Numbers of Polygones?

Ok I have seen it! It's Up page right corner in MoI ! :)