Stoyan,
as a first step make sure that there are no elements far from the origin in the model. Such can cause problems in the 3D calculation, like on your screenshot.
- open a floor plan
- select fit in window
- try to remove any unnecessary elements that are far from the model (based on my experience usually fill handles and things like that can appear quite far, after bringing DWGs and such in)
- repeat this with all floors
Try to export to 3Ds to see the results.
Marton
Marton Kiss
Chief Product Officer
GRAPHISOFT