Make several lines into one, not using join

I would like to create a single crv from several ones, but I want it to honestly be a single crv in the end.
When I use “join,” sometimes I can’t do certain things because Rhino will go back to picking only one of the original crvs, even though they are joined now.
Hope that makes sense.

Hello @Izabela,
If your curves are g2 continuous in their starts/ends (you can check with “gcon” command) you can merge two curves into one using “Matchcurve” with the join option

I think you are looking for the _Rebuild command.

Apart from what has been said, in a previous example that you posted, you had polycurves consisting of straight lines and true arcs. I would probably want to keep these as they are in a polycurve. But it all depends on the intend. You should probably provide more information about your workflow and about the “certain things” you can’t do with your polycurves.

Rebuild almost always changes the shape of a curve or polycurve.