New answers tagged tools
Have you thought about SketchUp? I have found it easy to learn and use, and it is backed by a pretty big 3D model repository. You can export 2D graphics from it too. Sketchup: http://www.sketchup.com/ (you can download the free Sketchup Make and try it out) Sketchup repository: https://3dwarehouse.sketchup.com/index.html
Things have developed since this post. You might try in5 (http://ajarproductions.com/), a plug-in that promises to do most of what you want.
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