Cylindrical like polysurface with two surfaces, want to convert to a single surface with one seam


I have two surfaces, one a mirror image of the other. They are tangent at the two places where they meet. I would like them to become a single surface with one seam, like the base cylinder shape has. What is the best way to do this? File is attached.ConvertingToSingleSeam.3dm(215.0 KB)


(Pascal Golay) #2

Hi Sam- Explode, ShrinkTrimmedSrf and then MergeSrf.



Great, works!
So ShrinkTrimmedSrf makes it slightly smaller (opposite of extend srf)? By how much? I always struggle with these invisible distances…

This object is for a file for another post I have going for squishing. Squishing is giving me a hard time, I’m going to post over there now, maybe you could take a quick look if you have a moment.

A great help as always!

(Willem Derks) #4

Hi Sam,

I cannot exact;ly answer your question, but FWIW:

Interesting read:
Note that there is also the command ShrinkTrimmedSrfToEdge


(Pascal Golay) #5

Hi Sam- if you turn on control points on one these surfaces before shrinking and then see how they change you’ll get the idea. Merging only works untrimmed surfaces and these are basically made into untrimmed surfaces by shrinking to the trimmed edge, which in this case is an isocurve. Shrinking a surface trimmed by an isocurve makes that edge like an untrimmed one.
See Help on ShrinkTrimmedSrf as well.


Got it, thanks guys


One more quick question on this: How do I choose which seam it merges at? It merged at the one on the front/top while I want it to merge on the back/bottom.


(Chris Kuether ) #8

My experience is that the choice of pick-point has influence here. Try undoing the mergesrf and try with different pick points.



That’s not doing it for me…


Hi Pascal,

Your method worked great, but I realized I need the seam on the other side, any way I can do this?



You should be able to use SrfSeam to rotate it back around to where you want it…


I tried that but it adds a second seam…

(Pascal Golay) #13

Hi Sam, if you UnrtimBorder after the shrink, it should pay attention to where the pick point is on MergeSrf.



That did it, thanks!