Normally I play with lightning tools like Grandma3D WYSIWYG or Vectorworks Spotlight. 2 weeks ago I played with this fantastic app mekorama at first time. In my opinion it,s a great beginner-tool for functional 3D designed gadgets. Please take a look in my Album and let me know what I can do better or rate my levels http://mekoramaforum.com/media/albums/levels-by-lichtfuerlau.697