Hi Jeff,

> Is there a quick start guide to the thinking/modelling process?

The best quick start guide are the video tutorials here:
http://moi3d.com/2.0/docs/tutorials.htm

Those do a step-by-step walkthrough for building a few simple models so you can see the overall strategy.

There's also an overview of the process on the introduction page here:
http://moi3d.com/2.0/docs/moi_introduction.htm


> I think if I think in terms similar to CNC it may be the right
> approach. i.e. take a slab, dimension it, carve/trim off what's
> not wanted and then add in detail (fillets, ...)

Yup, that's a pretty good way to think of it - although sometimes instead of only carving a piece you may model things as separate pieces and use boolean union to fuse them together into one new solid piece.

And also sometimes your "slab" can have somewhat different shapes, like for something that looks like a lathe result use Revolve to build the base form for that, something that's kind of tubular following a path use Sweep.


> Also, what the recommended process is to do these things.
> i.e. I found out I can't just draw curves on two sides of a
> solid, loft them then boolean trim them.

If you want to have a surface cut a solid into pieces, you need to make sure the surface is wide enough to actually divide the solid into 2 completely separate pieces.

If your surface does not actually cross the entire solid, then it would only cut kind of an infinitely thin slot in it instead of actually dividing it into different solid chunks, is that the kind of thing that you're asking about here? If you happen to have the model file that you are talking about if you could post that it would help to give you some more specific advice about that particular situation.


> Also, what would be a simple program to learn polygon modelling?

Try Silo: http://www.nevercenter.com/


> Is this related to "box" modelling that I see mentioned?

Yes, box modeling is one kind of strategy for polygon modeling.

 

> Is box-modelling taking a polygon-modeled box and deforming it?

Yup, that's correct. It starts with a box, then depending on what you want some pieces may be divided and some faces punched out to make protruding pieces, then the process repeated. Then the whole shape gets smoothed out by applying subdivision smoothing, which kind of takes the rough polygon cage and makes a melted down smooth result from it.

That process is somewhat more like sculpting where you're kind of pushing and pulling on a 3D cage to form your shape. It works best for more organic type shapes.

The process in MoI is kind of more like drawing where you're focused more on drawing curves and constructing pieces of your model from those profile curves. This works best for more mechanical type shapes.

- Michael