How to get an organic extrusion with rounded edges?


I would like to use a curve as a base shape, extrude it, and then fillet the edges. Also, something to make the extrusion more organic would be nice.

This is what I did so far:

baseShape.3dm (46.4 KB) (6.1 KB)

I have issues to get all edges round, and don’t really have an idea how to let the extrusion look more organic.

Does anyone have an idea how to do that?

Hi -

If you need “organic”, you should look at using SubD’s instead of filleting edges.
Something like this, perhaps:


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Hello @wim

Thank you very much! I think it looks generally good, but sometimes such stuff happens:

And is there a way to get everything more rounded?

Does anyone else have an idea to round it off better on all edges?

There are many many ways.
you could smooth the mesh, there are many tools to do that (Ngon, Yellow, Weavebird, …).
I filleted your curve before.
I like to use Dendro (not working on Mac !) and
making a positive and negative Offset, it suppress hard angle in 3D
then smoothing : there are many type of smoothing
Then quadremesh, the number of faces has a major effects
the Catmull & Clark subdivision or SubD to have a nice smooth volume
Effects of various paremeter, filter type, offset distance, fillet distance …

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Wow, beautiful! I love the first one! Since I am using macOS, is there an alternative way to do the same or something similar? And could you please share the script?

no problem to share the script
script (2).gh (18.5 KB)
If you want to replace Dendro for volume Offset, you could use IsoSurfacing. I did something long time ago

Except Dendro I don’t know if there is a good Mesh Offsetter for Rhino/Grashopper. Test that, it could help

Like it was said by @diff-arch it is not very good that Dendro is not working for Mac.

For the mesh smoothing, I think you’ll have to test many plugins to find the one that work best for you. But don’t forget that most mesh smoothing tools depends on the meshing.

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You could try inflating a mesh with Kangaroo, which can yield very puffy, blobby results.
The tricky thing is getting base mesh right, since the result will depend wildly on its topology.


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Hey, thank you!

With IsoSurfacing, I don’t really understand what must be done. What could be put here?

And with your second link, I came to this result:

It’s kind of funny because the edges really get rounded somehow, but it doesn’t seem like a good solution?

Yes, it’s sad that Dendro doesn’t work on macOS. @ryein, plsss let it work! :slightly_smiling_face:

Oh, interesting. Does it always react based on time? I’m not sure if this is what I am looking for, but it looks beautiful!

Yes, that’s part of the simulation, but at some point it usually converges/stops.

Sounds cool! Reminds me a bit of Marvelous Designer.

Do you maybe have an idea how to replace Dendro in the script before? :neutral_face:

Here’s an example that shows how to get a smooth result by inflating a mesh with Kangaroo 2. The result is similar to what is shown in your first reference image. It’s reminiscent of a balloon.

2022-08-26 14-35-31.2022-08-26 14_36_53 (17.4 KB)


Looks cool, thank you! How did you export this animation? :star_struck:

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I simply recorded the Rhino viewport with QuickTime and then transcoded the resulting MOV to GIF with FFmpeg.
I’ve set up an alias in my .z_profile that let’s me do that quickly and optionally change the framerate and size/resolution of the exported GIF.
If necessary the MOV can be trimmed beforehand in QuickTime.

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Very cool! Thank you

@laurent_delrieu and @diff-arch: Thank you again! Both seems to work great. It creates super beautiful results.

I just wonder now about shapes like that:

A.3dm (2.9 MB)

The hole in the A gets filled. It seems to not work with two curves. How can your scripts keep the shape of the A?

For shapes with internal boundary curves, you can use the ‘Boundary Surfaces’ component first to make the surface with holes first: (16.3 KB)

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Why is that Rhino file 2.9 MB? ‘File | Save Small’ reduces its size to 154K.

The same two curves internalized to a GH file is less than 2K in size. Or 3K when a Boundary component is added:
A (3.0 KB)

Less than 4K when Extrude is added:

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Thank you! But now it’s like a flat surface rounded in one direction. How is it possible to make it look like an inflated balloon?

If I just add ‘Boundary Surfaces’ to the previous script, it doesn’t work: