Offset srf and shell incorrect

Place this example also of tubing. Is an offset srf of 0.3 that one surface of shelling do not function. any set tolerance. I hope that in Rhino 6 this kind of operations function in a more robust.
(please check).
Tubing_ Offset e shelling error.3dm (182.9 KB)

Also check this, please!

It’s checked. If you set the file tolerance to a more reasonable number, like .001, then create the pipe from the curve, you’ll see that Shell does OK with it.

Keep in mind that changing the file tolerance in Rhino does not cause cause existing geometry to be regenerated at the new tolerance, so, the Pipe must be made at a reasonable tolerance to begin with.


Hi Pascal

After reading your post I played with the file @0.01 abs.tolerance and below are some of my findings:

  • could not make a pipe around the given curve starting at 4 mm and ending at 2 mm as designed with perfect matching of the outer skins (between pipe and model)
  • used shell command and the resulting pipe did not come solid
  • identified 12 naked edges, could only join 8 of them, then I am left with 4 small ones that look like point unless using the ZoomNaked command

Which brings me to my question. What are these tiny objects and how can they be fixed? Edge analysis tool calls them “naked” but Object description calls them “boundary”. Are they the same thing?

As a side note, I managed to make it a solid only after extracting the adjacent surfaces and then rebuild them.

Thank you


I missed the tapered part on the pipe… . It looks to me like the problem all comes back to making pipes, especially variable radius pipes across miters in non planar curves - in order for this to work cleanly, the tolerance has to be loose, and the result is too messy for offsetting.

Boundary edges are to distinguish from singular or seam edges… they can be naked or not, different question.