Hi Sophie, so unfortunately some of your new problems are fairly expected in nature.

> 1) When exporting .stl or .obj at both high and low poly counts, the geometry is not
> symmetrical and I get artifacts that are not trivial to remedy in other programs (like
> subsurf lumps and holes in Blender)

Applying subdivision surface smoothing on a mesh needs some careful arrangement in the mesh topology - the mesh needs to be specially designed to work well for subdivision smoothing and the mesh output from MoI is not designed for that, it's designed for rendering directly or 3D printing, not for applying sub-d smoothing on it.

You generally would need to reconstruct a mesh using retopologizing tools in order to get one suitable for sub-d smoothing. But usually with NURBS modeling you generate a smoothed object directly by things like fillets on it, so typically the model in its exported state is already in the smooth shape and does not have further sub-d smoothing applied on top of that.


> 2) When insetting/offsetting to create thickness, all calculations fail, whether I select a single surface at a time, or
> try for the whole object at once (ideal)

Unfortunately inset/offset in the geometry library that MoI uses is not particularly robust, it will get confused if you have various types of complex corner junctures which is easy to arrive at when you have several surfaces all at different angles to one another meeting at sharp corners. The offset of such structures is kind of more complicated than it would initially seem. You'll probably need to make an inner core piece by doing scaling rather than offsetting.


> I was careful (I thought) to make the two lines fall precisely on two dimensions, then rotated one 15°.
> Is it possible when I swept a surface between those curves, something moved a fraction of a degree?

Hmmm, difficult to say without seeing the specific 2 lines in their before and after rotated state.

Possibly you're running into the same thing discussed in this previous thread here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6835.1

That's where if you have angled something in one of the 2D views, if you then rotate it in the top view it's just a normal result that you will not have the same angle in the original projected view anymore...

But it's difficult to know for sure what you were running into here without seeing individual steps and the actual lines and so forth...

I'll take a look at your file and see if I can give you any feedback based off of that.

- Michael