Cycles (Caustics development)

Hi, is there any new development in cycles recarding caustics to make it better?
I’m asking because cycles caustics is very bad and if you want to get it look good you need to do some node tricks or go to YafaRay to render it there and composite later.

The only thing i can think of is that old metropolis sampling patch they were working on a while back. This patch produced artifacts so it needs a lot of work before it is usable. The developers are busy with 2.8, so I don’t think it will be worked on any time soon.

Cranking up the diffuse samples in branched path tracing works pretty well for me.

I just think Cycles at the moment cant create a good and sharp caustics no matter what is the settings.

I found this video how to create caustics in Yafaray and composite it later with cycles render image. https://www.youtube.com/watch?v=vZ7EtyhGeWo

You should have a look at LuxCoreRender
https://luxcorerender.org/download/

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Luxcorerender looks very promising option, I actually might do my next personal project using lux!

Hi, is there any new news to my original question about cycles caustics development?

It doesn’t seem very likely to improve any time soon. It would be best to use another render engine if you need caustics. One way they could improve caustics could be through supporting bidirectional path tracing, but that method is seen as too complex to get right and would prevent users from using many of the shader tricks that are possible in cycles because its a unidirectional path tracer:

I heard that metropolis sampling was better at producing caustics, but that would have to be rewritten at some point and it doesn’t seem to be on their roadmap:
https://wiki.blender.org/wiki/Source/Render/Cycles/Roadmap

Personally, I think that if supporting bidirectional path-tracing would keep us from using the non-physically correct shader tricks we have atm, I’d rather just keep cycles as a unidirectional path-tracer. I heard that appleseed produces good caustics because it supports photon mapping or something like that. When that feature is on, supposedly you don’t get consistent results on each frame, so they don’t want to add something like that to cycles.

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Would be the best way to add it (or just use LuxCore)

I doubt that we will see that in Cycles any time soon. What I heard is that some people use Cycles as the primary renderer and composite in a separate caustics pass done in LuxCore.

Thanks for your reply and provided links.

Lukas Stockner says that caustics use case is not that common in that video, maybe it’s mostly true in animation.

Many are using cycles for still images, if cycles caustics would be better i think many artists who are doing similar stuff what product photographers are doing, they would be using cycles even more for rendering.

I think caustics is everywhere if you look more closely.

How do you do that pass in LuxCore?

When using CPU only rendering, enable ‘Light Tracing’ and set it to 100% I think. You’d have to ensure the same light size and that you’ve disabled caustics in cycles.

Thanks, i need to try this! :slight_smile:

Unfortunately they focus on other stuff, I’m quite sad, but hey - not everyone thinks same as me, so I get it.

Is there way we can make blender developers take caustics more seriously?

Only coding yourself I guess, but it’s still hard to get your code approved and moved to production.

I don’t personally think its a big deal. From what I’ve seen luxcore render and appleseed are good free and opensource alternatives that work well for this.