Merge trimmed curved srf with untrimmed curved one

Hi All , I am just a beginner with rhino , I have made those two srf one trimmed the other and I want to merge them as one srf for pannelling … I tried mergesrf but it said edges are too far … tried matching them but doesn’t work … any help please ?
mergesrf.3dm (211.5 KB)

Merge Srf doesn’t work unless both surfaces are untrimmed.

Your surfaces have good zebras, not perfect, but good. They also have curves on their borders with a lot of spans, and without a good transition at that seam. They also have very different control point densities on either side of the seam.

If you’re using this for paneling anyway, maybe it’d be OK to slightly alter the quality of the surface?

Someone with better surfacing skills than me might have a better suggestion, but what I’d do as a workaround is to redo the whole thing using Network Surface, and maybe even use the rebuild surface command to soften the redone version.

Step by step:

  1. use Duplicate Edge to copy the seam.
  2. use Divide to split the seam into 5 equal segments, marked by points.
  3. use Extract Isocurve (you may need to toggle) to extract some lengthwise curves on both surfaces. when you create them, snap them to the points you made on the seam.
  4. join the the extracted isocurves.
  5. use near snap to put points on the joined isocurves on either side of the seam, nearby, maybe 12 units from the seam on either side.
  6. use the split command with those points and the joined curves to cut the middles out of the curves, then delete the middles.
  7. use Blend Curve to blend the curves you just deleted the middles of back together (this is for a smoother transition.
  8. use duplicate border on your polysurface. delete your polysurface or hide it.
  9. explode the duplicated border. lock the tiny end curve and the top end curve. select all, join. unlock.
  10. call the network surface command. pick the lenghwise curves as the first direction, the end curves as the second direction.
  11. try using Rebuild Surface on the result. Maybe try half as many Us and half as many Vs. Maybe this helps, maybe it doesn’t.

Here’s the result, in a new layer on your file.

mergesrf redo networksrf.3dm (1.2 MB)

Not as smooth as your polysurface, and one crisp corner on the bottom is now rounded, but it is one surface, and maybe ok for panelling purposes.

There are other ways to get here that might be better, but the ones I know involve tediously rebuilding the curves of your object.

Did this object come from another program or did you make it in Rhino?

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yeaaah… thanks alot for your explanation and the trial, it seems perfect to me and solved a big problem to me , it is alot of steps but seems to fix the issue … the biggest surface came from grasshopeer by rotating and moving a half circle then scaling the result by graphmapper and the other surface was done by sweep 2 in rhino after drafting the curves

That makes sense and explains why your isocurves don’t line up.

I’d love to hear what someone with better knowledge than me has to say about how to do this better. I expect there’s a faster way to get a good result. It probably involves making the second surface in precisely the right way.

Also, this post should probably be tagged as “rhino” rather than grasshopper. The people who know surfacing the best are rhino power users.

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post tag editing is done … & waiting for the same too