Do you guys know https://3dwarehouse.sketchup.com? No need for IFC support in my opinion...

...yes SketchUp and DragonFly probably are the best competitors for SH3D, but SH3D can create fastest drawings, and if they add a direct integration with PyFlow being both open sources, similar to Revit with Dynamo, could be more powerful and fastest than SketchUp.

https://github.com/wonderworks-software/PyFlow

...for another part, MASSIS, than was based on SH3D, could import IFC to their BIM projects, and this is just starting.