Glass caustics

[Jaroslav_Mikulik (Jaroslav Mikulík)]

Hello,

I want to ask you for advise on a glass shader. I try to make photorealistic glass. After a few renders, I am happy with results, dispersion looks pretty good, except for a small problem with blur when I use subsurface scattering, but the main problem is caustics. Is possible to make fake caustics based on shape of object to looks more realistic? Is it even possible to make realistic caustics in cycles in reasonable time without external render engines? Whenever I try to make some other node combination, it looks worse and worse and I am losing hope. Thanks for the advices.

[CarlG]

Check on blendswap or on this forum, I’m pretty sure I’ve seen a complex setup that also brightens.
Personally I just modulate for shadow for transparency based shadow control, which is probably not what you want.

For realistic patterns on stills, can’t you render out using Luxrender and simply add it as emission to the surface as a bake?

[moony]

Take a look at this - might be what you are looking for

Glass Caustics and Dispersion (v2.0)

Welcome to the new update of the Glass Caustics and Dispersion Shader! It’s been a bit past a year since I shared the original nodes, and I have been wanting to fix them for a while. The shader is not at the speed I would like it to render, but I am very happy with the look of the fake caustics. I will certainly be looking to optimize the nodes, and I already have a few ideas of how to tackle the problem. The caustics may, once again, change visually, but I want to prioritize speed. Only the “…

[Jaroslav_Mikulik (Jaroslav Mikulík)]

I want to do all in cycles, I have seen many tutorials, but no one is perfect for me.

[Jaroslav_Mikulik (Jaroslav Mikulík)]

Thanks, I see this file and use it, but result is not satisfying, it needs many settings by hand, I want node setup that works in every scene based on light.

[CarlG]

@Jaroslav_Mikulik

but no one is perfect for me

The one moony posted was the one I had in mind (I haven’t tried it or even looked at it myself). What do you mean not perfect? It’s faked, and with the limitations we have in Cycles, this is about as good as it’s gets. Needing controls is what you’re forced to when you’re not relying on physics (real caustics) - we cant’ manually “trace rays” in a fakery way, only create the result directly based on the few parameters that are available to us. More goes on in closures, but we don’t have access to it.

[moony]

@Jaroslav_Mikulik

Thanks, I see this file and use it, but result is not satisfying, it needs many settings by hand, I want node setup that works in every scene based on light.

LuxCoreRender is that way -----> https://luxcorerender.org/

If you absolutely insist that it must be Cycles, there was an experimental build kicking around a few years back that included metropolis light transport. This massively improved caustic handling in Cycles, but it was never implemented in master…and as far as I know, there are no plans to.

[Jaroslav_Mikulik (Jaroslav Mikulík)]

Ok. I will try it with LuxCoreRender. Have you some tip to convertor from cycles node to lux nodes? If I check internal use cycles nodes, it create totally different material and I dont want to start learning LuxCore nodes from the beginning.

[zeealpal]

I would generally recommend recreating the materials, it’s likely you will need less nodes to do so as the material setup is often simpler in LuxCoreRender

I’m happy to do a scene conversion, pm me if your interested.