Odd Intersection

In the attached file I have a number of arc–line pairs. I can join each pair. GCON says each is G1. But, if I intersect the pairs, there is no intersection (expecting a point).

Problem Intersect.zip (10.5 KB)

Hi -

When I open that file here, all the pairs are joined. I explode them all and run Intersect and get points as expected. Perhaps you need to post a file with the objects as they were before they were joined?

Yep, after joining they do intersect. Let me see if I can find an olde version before joining. The did not intersect before. That’s why they have irregular spacing. Some if the frames did intersect while others didn’t.

I overwrote the file with the problem in the starter. However, I found a similar problem with the same curves.

I started with Red. Then I copied to Purple.
In purple I joined the “arch” curves.

If I intersect, I get what I expect in red.
But in Purple I only get one intersection (where I expected two)

Problem Intersect.3dm (2.9 MB)

Can confirm - there’s something buggy going on with that purple linework! I created a plane using your “arch” geometry, intersected it with the long curve, created a line off the intersection point and then used Match to try to fix the issue. Still no intersection, where there definitely should be.

That is weird - Reparameterize > Automatic on the curve fixes it but it looks like a bug to me, thanks for the report.