Hi Yannada,
if your using Microstation you can actually export out IGES from a DGN file and bring it right into MOI. I am not sure if Autocad has the same capabilities or not, you might want to check for IGES exporter.
So at least with Microstation there is a work around. Take care.

Thank Michael, thats great news, In my opinion RealDWG is the way to go...

Hi Moe and thanks, to add Microstation is built upon the 'Parasolids' solids modeling toolkit; as such, it is always better to export in a "solids based" file format (such as Parasolids .x_t, ACIS .sat or STEP)

Autodesk also recommends ACIS SAT for Autocad, Revit, etc.
AutoCAD is based on the ACIS solids modeling kernel, so the ACIS .sat file format is a natural choice for exporting solids-based data with no loss in quality

Punch's ViaCAD is very reasonably priced. It imports .3dm files directly and will do things like trimming off solids with the imported surface, shelling a surface, thickening a surface - and exporting as .sat. Useful.

Hi Michael,

> re: Parasolid, it actually turns out that will not be an easy thing to add in anytime too soon.
> So sorry, that one is unfortunately not likely to happen right now.

That's ok Michael, just exported a STEP file from MoI and it works great, imported into my other apps as a single solid body
just the thing I wanted to see.

Thanks again.