Actually, I have no problem adding obj to KT or Maxwell, it is Revit (and generally Autodesk apps) that don't like obj files.... Also 3ds is quite an old format and even AutoCAD has an addon for 3ds export... Older versions had 3dsout as a standard command.

I want to complete modeling in Revit because it is easier for me.... I don't intend to use Moi for complicated models, Revit is not good (at least for now) for general modeling.