+1 on that. That's the general way I do for not too complex make2Ds
In Rhino 5 I'd
- Make2D the object,
- Use CurveBoolean to make an overall silhouette. This often fails with more complex models as the outlines may have gaps
In Illustrator the overall silhouette is used as a cutout for the drawing. Whatever other lines there are, lie on top of that. Sometimes I want to add some flat shading. In that case I'd use CurveBoolean or the Illustrators shape creation tool to fill specific areas. Again, this is likely to fail with more complex geometry.
So back to Greg's specific questions:
Yes, one curve, single outline.
Option for the single overall outline to have the cutout, if you need one.
The rest depends on personal workflow.
a) if you just need the lines, the front box should be a single closed, the back box should be a single open line with overlapped lines removed.
b) if you need the fills, both boxes should be closed curves.
I'd like to have independent options for both.
As with option b) on the two middle boxes and like @wim said, 19 or 20 closed curves.
But I'd still would like to have the option to get the internal curves as single lines, reasonably joined along edges of a surface.
To expand on Wim's statement, I'd like to think of Make2D as a kind of vector rendering engine. The current implementations are like a simple scanline render or viewport capture. Advanced render engines offer options for Alpha-Maps, Object- or Material-ID maps to effectively work with the result in post production. This is basically what I would wish for in a perfect Make2D.