couple questions for you shapie vets out there. I understand that we can't have non-manifold geo, but how about interpenetrating geometry? For instance, if I want a threaded post protruding out of the back of character, can I simply take my threaded model and push it into my object and clean up anything excess geo on the inside? Will this work correctly and pass the Shapeways initial upload check?
And what about moving parts? I saw the animated angel but I thought I read somewhere that we're not supposed to upload objects with very small tolerances or bridges?
Interpenetrating geometry should work ok, just make sure there's no faces on the same plane that share the same space. One of the most important tools you can have is NetFabb (the Basic version is free) - generally as long as the model looks good in NetFabb, it will upload to Shapeways ok.
For moving parts it depends upon the material, general rule of thumb is moving parts are fine in plastics. You'll find more info about sizing and spacing via the Materials page