I want to make a model for a 3d printing transforming figure, tips needed?

[Stedek97]

So, I want to make third party Transformers at Shapeways like I saw another man do. I will do the 3d models for them to print and they will be ball-jointed. Here is an idea of what I am talking about . So anyway, I have a few questions: 1. I have to make every single piece a separate model so they can be assembled as ball joints, right? Or can I just put them in a single model with space between so they don't fuse? 2. How to make sure the balls hold tight, but not too tight for rotating?

[curious aardvark]

shapeways should give you tolearances for joints.
But f you make the balls about 0.5mm less diameter than the socket, you should get a good fit.
But check with shapeways - you might get away with a smaller difference.
I think the minimum clearance for sls is about 0.1mm (so 0.2mm diameter difference) - but check first.
Oh yeah and as they use sls - you can actually send the model as a complete unit.