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I am an experienced Blender user but very beginner in Geometry Nodes.

I have an object onto which I am instancing small water droplets, using geo nodes. Maybe it is completely wrong but, to have more control, I have used 2 geo nodes modifiers - one for the very tiny droplets and one for the larger droplets.

Naturally, they now overlap at some points. Is there a way to call a sort of mask, where the 2nd geo nodes modifier would "mask out" the distribution in the first one?

Thanks!

pschinzel
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1 Answers1

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You can try a vertex group to transfer data between both modifiers...

I used Geometry Proximity against first pointcloud -larger droplets- to generate the density mask, then use it to distribute smaller instances. You will need a decent resolution in your mesh, but can subdivide inside GN.

First add the vertex group to the mesh and then type its name as output / input in modifiers. It's a bit tricky though, and took me some time to get it working...

nodes setup

and this would be the generated weight map...

generated weight map

alambre
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  • That seems like a really smart solution! Thanks for the input! I have however tried this, and it unfortunately doesn't work. The moment I apply the mask attribute to the second (small sphere) GN, it disappears and only the first one (big spheres) remains :/ Have you run into that issue as well? – pschinzel Feb 17 '22 at 10:30
  • you need to click the '+-' icon to switch modes and type the named attribute 'Mask', maybe that's your problem, it happened to me too... just uploaded a 3.1 blend here for you to test and see if it is an option – alambre Feb 17 '22 at 13:15
  • Awesome! That's great ;) Thanks! I've managed to get it working now. Not really sure what I did, but reconnecting some nodes did the trick. For now at least! haha Thank you very much for taking the time to help with this!! – pschinzel Feb 18 '22 at 14:35
  • I would love if this answer would be elaborated on. I really have no idea what to do when it comes to the vertex bit, and all you've shown is the node network for the last part of the answer. – WASasquatch Apr 13 '22 at 19:04
  • @WASasquatch there's a blend file to download in comments... but I should improve the answer I guess, the question was about using 2 modifiers but a single one would do it too... also the vertex group is not really needed, it just helps to visualize the mask... the confusing part is after naming the attribute output, clicking on the cross icon toggle of second modifier to be able to input same name again – alambre Apr 13 '22 at 19:48
  • @alambre Oh thanks. I'll check out the blend file. – WASasquatch Apr 15 '22 at 02:26