Blender 3D Modelling

I've been looking for a program to use for 3D CAD and I just found that Blender will export to AutoCAD DXF files which kills multiple birds with one stone.

Blender is available here:

http://www.blender3d.org/

You can also render your Blender model with POVRay after exporting it, POVRay is available here:

http://www.povray.org/