Sorry, I forgot your second question: How long does it take to make a model like this cylinder? I don't really know. I had only done one other model with MOI (or NURBS) before I started this cylinder, and I didn't know what I was doing. (I do have a lot of 3D experience, going back to the early 1980s, but that was with polygons, and NURBS is very different.) Learning is a slow process! A lot of that early work was poor and I had to go back and fix many things. There is still much on this model that can be better, because I accepted things that weren't really right, but were close enough that the errors would never be seen at the resolution of 3D printing. I want to say something about design. Companies like 'SolidWorks' teach people to do everything in 3D and then make 2D drawings from the 3D model. Except in simple cases, I think this is insane. I do all the design work in 2D (using 'Q-CAD'). Then I can import DXF drawings into MOI and build the model from these. It is very easy to make small changes in 2D; e.g. moving a screw location. Doing the same thing in 3D is very time consuming. I haven't tried to make a solid of this, but you can try it. I rather think that it is too complex.