The interaction between SU and BIM applications has always been a mixed bag. In the stone age SU had import plugins for Archicad and Autodesk Architectural Desktop that attempted to translate SU models into the native objects of these applications, with not-that-impressing results. Vertical faces were translated into walls, horizontal into slabs and oblique ones into roofs, and hole-cutting components into doors and windows. Good idea, but the results were usually messy with many redundant objects etc. unless your SU model was very simple, preferably a clean outer shell of a building.
Today SU models can be imported into Revit and Archicad either as imported objects or mass models. So SU can be used in a limited way to model things like furniture or other things that do not have to be parameter-driven. Also, I haven't found a way to smooth curved SU surfaces in either application, so in hidden-line 3D views SU-imported curved objects are fairly unusable. The same things apply largely to imported "mass models" too. As SU is a face-modeller, the usual massing tools don't work, but you can apply building elements to SU faces.
I am now doing my first full project in Revit. On the whole I feel it is quite a powerful tool, but it works quite differently from traditional CAD. It is almost totally about modelling/managing the building database, and if you look to work in a traditional CAD way you should probably look elsewhere.
I always say that my ideal BIM application would be a mixture of Revit and Archicad features, with the SketchUp interface.
Anssi
