Oh, this is wonderful! I didn’t have my hopes up that the feature set would return, but I’m happy to see it has. My schedule’s pretty packed in the near future, but I’ll see if I can make time and at least play around with it a bit.
The biggest issue I had with Nvidia’s caustics implementation in 4.0 was its’ complexity: you had to enable the feature in project settings, tell lights to cast caustics, tell surfaces to receive them, and adjust several different knobs to balance performance and quality. It seemed simply too consumptive of artist time to be widely useful. If by some miracle Nvidia’s managed to refactor the pipeline on using caustics, I think it could be extraordinary.
Something I’ve wanted to try since UE5 came out is using stained glass to cast colored shadows, and having that light up a room in a given light color. That would require the caustics generation, shadowing, and lumen systems to all talk to one another, but it’s an affect I’d love to achieve.