Hi PAQ,
I just did a test with Hexagon and an OBJ import/conversion with the newer stl2step converter..

I revieved the error also from a default export from Hexagon.. I then did an export and deselected "Export UV's and Export Normals" and the import into stl2step succeeded!



I havnt tested to see if it was one or the other yet, and I dont know what you have in Modo upon export, but you may look at eliminating some of this information from the export to get the model in... :o