When I first started learning geometry nodes a couple years back I attempted to make a rain simulator. It was insanely complicated and laggy. I was rendering everything as meshes, procedurally animating rain splashes for each drop - everything was overkill. So I relegated it to the pile of failed projects and moved on. But while I abandoned it, I always wanted to return to the idea of creating a rain effect where you could easily drop into a scene without everything grinding to a halt. Then recently I randomly had a thought on how to approach the problem in a much simpler way, so it’s lightweight and comfortably renders in realtime in Eevee.
It’s built around the idea of generating a sudo wetmap that you can pass onto the shader editor and plug into your roughness. The rain is rendered as points, so you can really crank the density up before things slow down, and the geometry node graph is simple enough experiment with without melting your brain. It’s also possible to customise the rain animation to generate more interesting visuals as the rain hits the ground - but while I’m playing with the best solution I’ve left it out of the demo for now.
The workflow of storing attributes to pass onto the shader editor is such a powerful one. I’ll definitely be playing more with it in future.
Demo file is up on a fresh discord for anyone who want to play around and improve on this https://discord.gg/T2QVsDkj
