Thanks Michael,
I realize I can explain you exactly what I'm trying to achieve, maybe (if you think it's a usefull feature) you can easily integrate into MOI.
I need to export 3D geometry to DXF, but current exporter only allow to generate visible/hidden lines.
AI/PDF exporter can manage silhouettes/outlines choosing colors/layer names/line widths.
So AI exporter is good but it generates a lot of duplicate lines.
One last thing, every exporter generates all lines, I would need to "simplify" somehow visual appareance of DXF result.

So I create the attached script. It's not complete but it *should* work. Is very simple but the tests are encouraging

I would like to know if it will be possible to integrate into engine, I think will be useful for "technical illustration"