Hi all,
I’m working in Grasshopper to generate a surface from a closed curve. I’ve attached the curve I’m using. When I apply Patch, the resulting surface has twisted edges, and I’d like the surface to remain aligned with the input boundary. I’ve tried adjusting Spans and Flexibility, but without much success.
Do you have any advice on how to keep the surface tight to the curve without splitting it into smaller lofted surfaces?
Edge Surface.gh (5.2 KB)
Edge Surface2.gh (12.4 KB)
Try using lunchbox`s patch
Sometimes you need more “defining” features, such as points, yet keeping in mind a patch is still a patch:
Patch Surface.gh (22.9 KB)
Other than that, you’ll have to resort to something more involved, or something like what @mario.vergara has suggested—and yet your boundary curve still will not be 100% flushed with your patch surface.
How does it compare to the original curve? Image please?
It’s a complex shape.
Is it any better than this? Standard R7, looks very slightly worse in R8 but sill acceptable.
P.S. Looks fine to me with ‘Flexibility’ = 1.
Thank you all for the suggestions. I’d like to give a bit more context so you can better understand why I’m trying to have the surface close to the edge.
I’m working with Erwin Hauer patterns, and when I build the basic component, my goal is to join the two sides into one continuous surface if possible. Of course, if the edge becomes distorted, the surfaces can’t join cleanly, which is why Patch is giving me problems.
Do you think SubD could be a better approach here? It might be a longer workflow, but it would be more interesting for me if I could treat the whole element as a single, smooth surface rather than splitting it into multiple lofts.
Thanks again for all your help.
Edge Surface3.gh (10.8 KB)
The surface looks very close the edges to me. What’s the problem? Mentioning the client’s name DOES NOTHING for me.
It’s close, but it still doesn’t join the Breps into a single Brep, as you can see from my image. @Joseph_Oster I did not mention the client’s name. 
I’m sharing this context so you can better understand the broader picture and the reason behind my question. Thanks
If you may also accept meshes, you can mesh the surface and pull the boundary vertexes to the original curves
… many of those seems a perfect job for SubDs and hard creases.
Instead of deforming a unit cell Brep and then having to handle every open edge, sticking, etc etc… with SubD things could be simple.
Hard to tell without seeing the whole project. This is just a guess…
Yes, I agree — the workflow is to create the module in Grasshopper first and then propagate it across a surface. My only concern is the limited flexibility of SubD inside Grasshopper. I haven’t explored whether there are plug‑ins dedicated specifically to SubD workflows.
@Gianfranco “brute force” will save you for this rare case:
