I tried to join 2 curves, but it failed, and when looking closer to the lines I saw that one of them is dotted. searched the manual but I found nothing on this.

tnx
wim

the 3dm file attached

found it!

that curve was initially a straight line, which was joined to other curves, but I had to change some points, so I separated the joined curve, and the straight line was thereby converted to a freeform curve, and the control lines are at the same place of the straight line itself, which gives a dotted result.
I think I found why the lines would not join, I selected them in front view, and probably had another line behind that selected too. selecting in 3d view solved it.

rgds
wim

Hi wim, it sounds like you've got it all figured out, but just in case the dotted line is what's called the "control polygon hull" - it's just a line that connects all the control points together so you have some indication of their ordering:



If your control points are all in a straight line, then that dotted control hull will be going right over top of the curve itself.

- Michael