Curves won't join

I have two curves connected by their endpoints that do not want to join. I made sure there is no overlap. I can’t figure out why. Maybe I’m missing something here. this is strange. This has never happened before.
the curved curve was made by projecting a curve onto a mesh and the straight one with the polyline cpmmand, if that helps. I tried rebuilding the curve but still won’t join . Any idea?
Thank you

curves wont join.3dm (58.5 KB)

OK, that is a pretty interesting one. First, your two long curves are closed - so they can’t join to anything. Usually this means duplicates have been joined together, but not in your case.

Explode the 4 sided figure and then use SelDup - you will have 124 duplicated tiny segments! Delete those. I would probably suggest joining the other 124 backtogether first, then rebuilding to one smooth curve.

The other long curve is even more interesting - it says closed, but can’t be exploded. In fact, it’s a single curve that has been folded in the middle back on itself… How did you do that?

I would simply suggest re-making it. Probably easier to re-make the other one with 124 segments as well.

Thank you! I tried exploding the unexplodable curve first and didnt work so I didnt even think of exploding the other one. I’ll explain what happened.
This came from a sketchup export which was brought in as meshes. The original geometry is pipes with a centerline. I projected the centerline onto the beams to get a curve along the top surface of the beam which is what I was looking for. This is probably how the duplicates were created without me noticing.

Thanks again!

Hello - SelOpenCrv and SelClosedCrv can help diagnose these…


Don’t know if this would have helped in your particular case, but as a general rule it’s a good idea to keep your eye on the command line to see the command result messages. Often it will report results that seem “really wacky” - which will clue you that what’s happened isn’t really what you expected, even if it’s no more help than that. Sometimes, though, it will actually perform the forehead slap for you and you can readjust your thinking and carry on.

Thanks @pascal

thank you for the tip @AlW