I am a mechanical engineer with experience in the field of autocad modelling for more than 12 years.
I lead the design department in a workshop so it's almost my daily job 2d&3d.
Also available on:
1)Shapeways
https://www.shapeways.com/shops/mapleo-designs
2)Thingiverse
https://www.thingiverse.com/MapLeo/about
3) myminifactory...