caustic cache and light tracing

[lacilaci]

One current solution to sds seems to be caustic cache... can we have per object setting for this cache?

To explain:

I have a scene with a pool(of course) but in this scene there will be few objects also causing caustics. I would like to be able to enable caustic cache per object on demand! I'm thinking the inverse option to "use photongi" option in materials.

The way it would work, is that the caustic cache would be enabled only if the object has the property set on (generate caustic cache for example). You don't usually need caustics to be generated for most of objects in a scene and caustic cache is also a bit limited so maybe it could be an object property..?

Another sub-question to this is if this cache could be used with lighttracing... So a scene that includes a pool and a glass of water would use 2 ways of doing caustics.. pool would do cache(SDS) and glass of water or just all rest of the scene would use lighttracing. Both being mutually exclusive so pool water body would not do any lighttracing for example...

I know this sounds like a overcomplicated solution but until we get lighttracingVM there it might provide something...

[lacilaci]

here for example:

I'm willing to wait for the caustics in the green - pool, but I'm not waiting for the nor want the others in the red...
Also.. since these caustic particles cover several pixels at once they won't get denoised!

[lacilaci]

here.. near 2000 samples.. sds caustics are almost usable, but those firefly particles aren't going anywhere... OIDN cannot filter them out either

EDIT:
Is clamping even affecting caustic cache??

[provisory]

If you don't use periodic cache, you could try this:

- hide those objects that you don't want to receive caustics
- generate and write to file the caustics cache
- unhide the objects
- use the previously generated caustics cache for rendering

[lacilaci]

If you don't use periodic cache, you could try this:

- hide those objects that you don't want to receive caustics
- generate and write to file the caustics cache
- unhide the objects
- use the previously generated caustics cache for rendering

You're the best!
Will have to do some crazy mesh modifications but this seems to kinda work...