Creating tubes

I have a need to create a tube with a tight bend radius. Rhino performs this construct but the tube created folds over itself on the inside radius. I want to eliminate this fold and trim at the tube where it intersects itself. Does anyone have a technique for either constructing the tube without the fold or trimming off the fold after construction.

Also a wish for R6 - the automated creation of an irregular closed object centerline.

If you can post a file of what you have done it will give us an idea of what you are trying to do.

All my best … Danny

I tried to paste some pictures in the original post but was not successful. Here is a file that is representative. Tube.3dm (456.4 KB)

I think it’s going to be tricky to make cleanly in all cases - there might be blood, but the basic incisions to make are like so, I would say:

The red is a NetworkSrf.


This might not always be possible, but it works; perfectly smooth, no self-intersecting surfaces, relatively simple modeling.

I used a narrow parabola for this example (red); it’s a pretty small curve, and a relatively large diameter cylindrical surface (green) smoothly navigating the sharp curve. The solution; Sweep 1 with the small radius curve on the inside and the circle (electric blue) on the outside.

SmRadCrvLgDiaPipe.3dm (258.2 KB)

Best regards,

Thank you for your help

Depending on the accuracy you need, this technique is very simple and fast.
I show points, select the ones that overlaps, start MoveUVN and move the “Smoothing - U” slider to the right as much as needed.
You’ll find the before/after in the attached file.
SmoothPipe.3dm (687.2 KB)