I just read about http://www.sweethome3d.eu through a Sourceforge mailing. Apparently, it is a cross-platform (Windows, OSX and Linux) and Open Source home modeling application, with the possibility of running online. The export to 2D drawings uses Scalable Vector Graphics (SVG), which is slightly similar to PDF, but in an open XML-based format and the 3D model can be exported into an OBJ file (the old ASCII-format from Alias Wavefront software, before it became Maya).
When I was collecting ideas for a book chapter on BIM (that seemed to never have emerged after that), I collected 10 ideas, which I believe still reflect good recommendations to improve the usage of BIM during the early design phases. These ideas are related to BIM software, but you can apply them in any flavor, as long as you can model with Building Elements, Spaces and have control over representation. Introduction This article gives an overview of several recommendations and tips, to better apply BIM applications and BIM methodologies, in the context of the early design phases. Many of these tips are applicable in any BIM application and they are based on experience gathered from teaching, researching and using BIM software. Sometimes they could help software developers to improve the workflow of their particular BIM implementation. Tip 1 : Gradually increase the amount of information In the early design phases, the architect makes assumptions and lays out the main design in