Metaballs: 3.3 Geometry Nodes test

With blender 3.3 comes the Volume Cube node, and with it a whole set of new abilities.

One of the amazing possibilities is real metaballs. By using distances to create points, and comparing these using the smooth minimum node, you can easily create custom metaballs, complete with smoothing and color blending.

Here’s a project file so you can try it out and play around with the settings:

Files

metaballs.blend (4.0 MB)
(An example file, contains the scene shown above. )
metaball-assets.blend (1.6 MB)
(A file containing all of the nodegroups, ready for you to drop in your asset folder. Includes thumbnails. )

If you have any suggestions or questions, let me know!

14 Likes

super cool ! well done !!

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I’m quite a bit behind the curve on Geometry Nodes - as in, I don’t understand them at all yet and I’ve spent almost no time with them :sweat_smile: Can you explain why this method creates “real” metaballs as opposed to the current metaball system?

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As of 3.2 and earlier, aside from a few workarounds, the only option we had was to convert points to spherical volumes, and convert this to a mesh.

Like so:


They look fine, but they are missing one of the defining characteristics: Merging.

Here’s what two metaball objects look like:

They have a merging influence. They actually create a sort of smoothing, and a bridge between them.

Also, when in the same position, the volumes are added together, making the ball twice the size:

For comparison, here’s what a simple setup with my system looks like:

This is possible through the smooth maximum node, which allows you to compare the distance between two points, and use the smoothing distance to determine the merging influence.

To test this, you can try changing the distance setting on one of the metaball nodes.
imageimage

6 Likes

Thanks a lot! I’m looking forward to using this in some larger projects when it becomes stable.

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I just added a new file, for those of you who like the asset browser.


I’ve also added custom thumbnails and tags.

You can find it in the files dropdown on the first post. Just drop it in your asset folder and you’re good to go!

EDIT: Purged some unused data blocks that were significantly increasing storage.

5 Likes

I featured you on BlenderNation, have a great weekend!

1 Like

Great project! The volume cube node node is much faster than cube marching or smoothing. I would recommend you to switch common SDF conventions (inside is -ve and outside is +ve). It will make your work much easier and you will be able to copy SDF formulas off the Internet ( Inigo Quilez :: computer graphics, mathematics, shaders, fractals, demoscene and more (iquilezles.org)). I would have advised you to look at my old SDF Geometry nodes file for the node version of these formulas, but it uses legacy attribute nodes. So I doubt it would be of much help. Nevertheless you can always ask me if you face any issues as I have experience with SDFs in GN .

2 Likes

Nice project. Curious as to how this will work with creating a sculpting base.

Thanks for the feature @bartv!
    I really appreciate it!

Thanks for the tips @Xeofrios!
    I’ll do some more research and see what I can do with it!

Thanks for the compliments @UnCommonGrafx!
    I think it will open up a lot of cool possibilities!