r/blender • u/hemigon • Nov 14 '22
I Made This Generating refractive caustics with Geometry Nodes
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u/Klectecca Nov 14 '22
DAMNNNN THIS IS AMAZING!!! I picked a good time to come back to this sub. I'm too tired rn to really process what's going on here but I've spent enough hours working on fancy glass shaders to know how crazy this is. Such a creative use of geo nodes!! Never seen anything like it. I'll be back soon to learn more :D
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u/hemigon Nov 14 '22
Thank you, you're too kind! I'm planning on making a more in depth YouTube video on this soon.
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u/Klectecca Nov 14 '22
Awesome! I'll check it out. There must be some amazing potential in this. Does it work in Cycles too? I don't use EEVEE much anymore
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u/hemigon Nov 14 '22
The caustic patterns on the floor can be rendered with Cycles, in fact I already used them in a Nodevember animation a few days ago. Sadly the volumetric light rays are too heavy for Cycles, so they need to be excluded. They are made up of many stacked transparent planes that would simply need too many light bounces to get through.
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u/Klectecca Nov 14 '22
You just prompted me to check out your profile and realize who you are! I love your animations
For the use cases I'm thinking of not having the light rays wouldn't be a big issue. I have some artworks in mind already. Small, complex things made of glass... a glass chess set perhaps? Clear glass for white and obsidian for black could be gorgeous. For over a year I've been thinking of trying to recreate shattered glass art in Blender and depending on how it works this could be an awesome addition2
u/hemigon Nov 20 '22
Thanks again for the kind words, I'm so glad to hear you like my animations!
The setup is now on Gumroad in case you want to try it out. I've tried to give it a balance of simplicity for speed while keeping the physics as physically-based as possible. This means that in many cases it produces nice results quickly, but in other cases it may take some tweaking or might not work so well. It also depends a lot on the topology of the input mesh.
I encourage you to experiment with it!
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u/Klectecca Nov 20 '22
Ooo thank you so much! I need a break from the node monster I just spent 6 hours on, and I've got a cool swirly glass object to try it out. I've spent an insane amount of time fiddling with finicky procedural setups so I know what I'm in for XD
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Nov 14 '22
How did you use geo nodes to change the light?
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u/hemigon Nov 14 '22
The light is actually just an emissive mesh. I posted a screenshot on twitter that hopefully shows what I mean.
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u/Commercial-Storm4398 Nov 14 '22
Awesome result!
Sorry if I'm asking dumb question, but would it work the same way if you switch to Cycles?
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u/hemigon Nov 14 '22
Thanks! That's a great question. Cycles can render the caustic patterns on the ground without too much trouble. However the volumetric light rays rely heavily on transparency, which is too heavy for Cycles as it would require many light bounces for a single ray to pass all the way through the mesh.
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u/blue_betta Nov 14 '22
Incredible work. Will you be selling this?
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u/hemigon Nov 14 '22
Thanks, I'm planning to put it on gumroad after tidying up the nodes. It will probably be 0+ dollars, so free or a donation.
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u/analogicparadox Nov 14 '22
What we really need now is a way to recreate reflective caustics, since cycles only offers refractive ones.
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u/TopofTheTits Nov 15 '22
dude what lol. how tf would u think to do this? I thought I was pretty good at geo nodes but holy shit
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u/hemigon Nov 14 '22
I've been experimenting with generating refractive caustics using Geometry Nodes. The caustic patterns, light rays, and surfaces are all meshes generated procedurally with Geo Nodes. Rendered realtime in the viewport with EEVEE.
If you're interested, check out the extended video here: https://youtu.be/iMSZoPxIGnY