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Tubes Intersection


Super Moderator
I found this post in the Requests or Problems community, posted by German Jimena several weeks ago. Unfortunately, I wasn't able to copy the pictures that went along with the dialog.


I'm working with CATIA and have a problem

I'm making a structure, formed with empty tubes, 1 diameter width, different diameters

I've made the structure with lines and points, thinking in having a clear idea of the structure since the plans are not thad good. Here it is.

Now, I decided to do ribs in every line with the adecuate profile of that bar. But then I found a problem with the points where the tubes are joint. Here it is a rib through an arc

And here, the problem with de union

It looks unreal an ugly. Not very profesional. Also, it appears the following warning, which i dont know if its or not relevant.

I tried to fix this doing this.

I do a pad in the end of the first rib, equal in length to half of the diameter of the tube that will intersect it.

And now, instead of a rib i use a "pad up to next" I though it would give a better look, more "welded", not "one on top of the other". But instead i get the following error.

Topological operators: impossible relimitation on the main part. - Change specifications.

How can i solve this error? Am i working the wrong way with this structure? How can i turn the line a points structure into a tube structure? How can i make a nice modeling of the weldings?

Thanks in advance


Last edited:


Super Moderator
Hello Share,

I suggest trimming the ends of each tube with a plane (or a surface if the tubes are not straight) and using a Split operation to get the mitered (professional) intersections you want.

I like your approach of starting with a set of points and lines to solve this design problem.

Are you creating an assembly of tubes (each tube is a single CATPart file)? Or, are you make a single CATPart (with each tube defined in a different Body)?