Check out http://www.osarch.org/ http://www.osarch.org/ which is a quite vibrant community of open source architecture software and users. Architects can use B

Check out http://www.osarch.org/ http://www.osarch.org/ which is a quite vibrant community of open source architecture software and users. Architects can use Blender. It has better BIM support than all the commercial offerings, better rendering, is free, stable, cross-platform, etc. Not brilliant on drawing output, but that is under active development and is already OK. You can also export to FreeCAD and then do drawings from there.