Reflected caustics dont produce volumetric lighting

[jpjapers_1]

I was playing around with lighting tests and got playing with caustics and a mirror ball. So i built a quick test setup and soon realised that while the light thats hitting the mirror ball emits as expected with volumetric streaks, the reflected light bouncing from the ball to the walls does not produce the same ‘god rays’ but still displays the correct brightness on the walls.

I would assume the reflected light would infact produce a ray as bright as the incoming light when reflected of a perfect mirror this way and should therefore produce a beam.
Is this a restriction of the caustics solver? Im aware this is a pretty niche use case.

[tom_grimes]

Known limitation. “Caustics inside volumes are still calculated the old way and are not accelerated by the new solver.” from https://coronarenderer.freshdesk.com/support/solutions/articles/12000056738-how-to-render-caustics-with-the-new-caustics-solver-

[jpjapers_1]

@TomG

Known limitation. “Caustics inside volumes are still calculated the old way and are not accelerated by the new solver.” from https://coronarenderer.freshdesk.com/support/solutions/articles/12000056738-how-to-render-caustics-with-the-new-caustics-solver-

Thats interesting. Why then does the reflected light on the walls render so quickly if its not accelerated by the new solver if thats the case?

[romullus]

@Jpjapers

Thats interesting. Why then does the reflected light on the walls render so quickly if its not accelerated by the new solver if thats the case?

Because a wall is a surface, not a volume?

[tom_grimes]

Yep, it’s a surface not a volume Calculating things through a volume is a different set of calculations than working out what happens on a surface. So reflecting caustics onto any sort of surface, done, works. But reflecting caustics through a volume, a known limitation. Finding where the reflected light ends up is one thing - tracing it every step of the way through a volume is quite another.

[jpjapers_1]

Ah i misunderstood what the sentence was saying. I thought it meant all caustics that originate from inside a volume, not just caustics that affect the volume internally.
Thanks anyway

[marchik]

@Jpjapers

Ah i misunderstood what the sentence was saying. I thought it meant all caustics that originate from inside a volume, not just caustics that affect the volume internally.
Thanks anyway

It was the very first thing i’ve checked almost 2 years ago after caustics release [https://forum.corona-renderer.com/ Caustics playground! #msg147937](https://forum.corona-renderer.com/ Caustics playground! #msg147937)

it’s a pity that this has not been resolved so far, because Vray has such a possibility

[jpjapers_1]

@marchik

It was the very first thing i’ve checked almost 2 years ago after caustics release [https://forum.corona-renderer.com/ Caustics playground! #msg147937](https://forum.corona-renderer.com/ Caustics playground! #msg147937)

it’s a pity that this has not been resolved so far, because Vray has such a possibility

I almost asked this in the caustics playground thread but it was dead so i didnt. It was just part of an idea i had for a personal project so its no big deal . Just a bit of a shame because its not very convincing without the rays.