Interoperability amongst BIM tools is obviously the goal in the OpenBIM movement. However, just exporting geometry to another application isn't enough if the format is not optimized. Many tools, like Sketchup and eQuest, operate best with simplified models using only single-plane walls, floors, roofs, openings, etc.
There are several analysis tools available on other platforms (for instance, we use Sefaira for Sketchup for early-concept energy analysis), and we generally need to either A) export the ArchiCAD model and clean up the multiple layers of construction, or B) start the model from scratch.
ArchiCAD models inherently have all of the information they need to output simplified geometry. All extruded tools utilize a reference line or plane. Sometimes, that's the only component we care about, but it cannot be currently isolated.
Though this could be built into an export add-on, I think there's a better way. We already have Partial Structure Display. Why not add another option: Reference Planes Only. This would show the bare-bones 3D form of any design, which has any number of applications inside and outside of ArchiCAD.
Architects like to deconstruct things, and this would give us a simple way to distill the model down to its purest essence. It would probably also be a wicked-fast way to work in complex 3D models.