Pdms 3D models in Dblisting format that can be downloaded for free.
If you have any more interesting examples, that you would like to share please send me and I will publish it here.
This post is updating, so you will find new models periodically.
If you need to create hexahedron primitive in Paragon module, as a part of you detail.
And you don`t wont to waste your time its good idea to write simple macro.
Sample in attachment
Just navigate to Category or Geometry set of your category and insert this script into your CommandWindow :