An easy way to get outlines of shape

Is there a Rhino Command that can get the silhouette of this voronoi, so I can make a simple extrusion? Thank you for taking the time to look.

Maybe the Silhouette command?

I’ve tried to play around with it, but Silhouette mode also keeps the middle part of each of the surfaces for some reason

They’re just curves. Delete the ones you don’t need.

Oh sorry, I mean like. It’s not distinguishing the edges from the center, so it’s a fair bit tedious to clean up, but I suppose im looking for an easier way to clean it up.

Which your suggestions are helpful, I think im a bit stressed that it’s not working out. Pride and such.

Maybe if you posted a portion of the file and provided a little clarificaiton on what you’re specifically after, someone with far more Rhino skills than I may weigh in with better ideas.


To be honest, the best way to handle this situation is maybe to start over with a better strategy. Given your vast multitude of closed areas defined by all the curves, there’s no way for Rhino to understand what is supposed to be a hole and what is supposed to remain solid. As a human you might be able to pick those out individually, but Rhino isn’t a human. (who knows, maybe AI will be able to do this in the future)

If you are working with Grasshopper, Voronoi cells are closed curves. You should offset these just to the inside if you want clean results. Rhino V8’s Offset function is much better than V7’s in this aspect as well.

you can also use MeshOutline, that of course will create polylines with the resolution depending on your mesh or displaymesh., with a bit or rework rebuilding the curves that might suffice.

MeshOutline does not act on curves, only surfaces or meshes.

who would need something that acts on curves when surfaces are all we have here?

Where do you see surfaces? All I see is curves. Since all he posted was an image, no way to know. The output of a GH Voronoi 2D is curves.

in the third post the OP talks about how silhouette keeps the center of the surfaces, my conclusion was to use MeshOutline. does that make sense?

Yeah except the “middle part of each surfaces” doesn’t mean anything to me, so I’m still not sure there are any.

thats ok you dont have to be sure, MeshOutline might help if indeed he has the surfaces he is talking about :man_shrugging:

It’s hard to tell without a Rhino file, but my first thought is that you have a combination of closed curves and open curves, and you really only want to make something from the closed curves.

So, I’d extrude everything with solid=yes. Then I’d get rid of the surfaces that aren’t closed by SelSrf and delete those. Then I’d boolean union everything that’s left. Then I’d run MergeAllCoplanarFaces on everything.

Or you might need to run SelClosedCrv, then do the extrude.

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You are absolutely correct.

However I did try to reproduce in GH what he posted as an image. Except for the density/randomness factor, this looks strikingly similar to me:

And I don’t see how to get from there (curves) to any easy, coherent surface production that could then be used with MeshOutline to produce a desired result…

But of course, this is all idle speculation.

i am sure MeshOutline can help him either now or at a later point in the process. silhouette is just not very helpful in many situations in general, wishing it to function more like MeshOutline apart from the resulting polylines of course.

which is reason enough to conclude further speculations for now.

Oh dear, so many people. Allow me to post the grasshopper file this all derives from. I manually extruded the planes in rhino instead of grasshopper.

i sincerely apologize for keeping you all waiting.

Attractor Points - (6.9 KB)

Maybe this is useless, but I was thinking maybe you can just join all the closed curve, use planarsrf to turn them into surfaces, (setpt to the same z coordiante in case they are not aligned) do a simple booleanunion to all the surface and dupborder at the end.

Surprisingly enough, this worked haha! Thank you, and thank you everyone else who did reply. Im sorry If I wasn’t exactly clear beforehand, ill try to post the files earlier