Hi Rado, I'm sorry but I'm still not quite fully understanding. I'm getting a bit lost when you get to the tracing part - it looks like you want to create some curves that are not only in that plane that you cut with but also some of the pieces that are behind it as well?

Instead of tracing those by drawing new 3D curves, you could instead save out to AI format which will produce a flattened 2D snapshot of the edges in your model, it seems like that would produce the flattened traced curves that you want?

If you want to produce that slanted section as the sort of "level" reference, then you could use Orient to align that face to the Top, Front, or Right views, and then when you export to .AI format there is a choice of which view you want to export so you can use the one you aligned to. Or it is also possible to do the reverse and keep your model in the same spot and instead re-orient the Top/Front/Right views to be looking down at a particular face, you can use the View > CPlane tool to do that one.

But it sounds like saving to AI format would generate the flattened traced curves you need, then you can read that AI file back in to MoI for further processing like deleting or trimming portions of it or whatever.

Does that help with what you need?

Also one other note - you don't need to draw new curves over top of edges, you can extract edges as regular curve objects by selecting the edges (select 1 and then do Ctrl+A to select all of them) and then doing a copy and paste (Ctrl+C then Ctrl+V). Then you will have a bunch of regular curve objects in the same locations of the edges of the solid, and you can hide or delete the solid and then just work on the curves after that.

- Michael