I know this is an old guy question, but I often model things in Autocad and import them into sketchup pro. A few versions ago it was pretty seamless and the Autocad solids remained as solids. If I painted a glass material, the entire object would be transparent.
In the last few versions, I have had to explode everything twice and break the model into individual surfaces to apply a transparent texture to. I also have to apply it to every single face. Which can be tedious. Is there any way to import a CAD model so it remains as a series of solids?