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Laser not visible in volume
Posted: Sat Dec 25, 2021 11:53 pm
by syhrdrjrt
Every time I try something with lasers and glass in Luxcore I go crazy after a short time. This time I have a prism, three lasers and an inner and outer volume. The lasers are always visible outside the prism, but inside ONLY if you select rough glass. No other settings have been changed. Such absolutely strange errors always drive me crazy after a short time when I try to do something. Maybe someone knows how to fix this
Re: Laser not visible in volume
Posted: Sun Dec 26, 2021 12:57 am
by Dade
They are called SDS (Specular-Diffuse-Specular) paths and they require a very specific algorithm to be able to render them. You need to enable caustic cache (on volumes) to be able to see them.
By using rough glass you transform SDS paths in GDG (Glossy-Diffuse-Glossy) paths and they can be rendered by BiDir or with Path+Light tracing enabled.
Re: Laser not visible in volume
Posted: Sun Dec 26, 2021 1:28 pm
by syhrdrjrt
Thanks for the reply, wouldn't it be possible to give a very tiny base roughness to the normal glass as well, making everything easier? Also more intuitive?
Re: Laser not visible in volume
Posted: Sun Dec 26, 2021 1:49 pm
by Sharlybg
Dade wrote: Sun Dec 26, 2021 12:57 am
They are called SDS (Specular-Diffuse-Specular) paths and they require a very specific algorithm to be able to render them. You need to enable caustic cache (on volumes) to be able to see them.
By using rough glass you transform SDS paths in GDG (Glossy-Diffuse-Glossy) paths and they can be rendered by BiDir or with Path+Light tracing enabled.
Never had this in Mind.
Re: Laser not visible in volume
Posted: Sun Dec 26, 2021 2:56 pm
by Dade
syhrdrjrt wrote: Sun Dec 26, 2021 1:28 pm
wouldn't it be possible to give a very tiny base roughness to the normal glass as well, making everything easier? Also more intuitive?
It wouldn't be glass anymore but rough glass
Re: Laser not visible in volume
Posted: Sun Dec 26, 2021 3:39 pm
by syhrdrjrt
Yes, but with dispersion. Is there such a thing as perfectly smooth glass? Isn't there always at least a bit of roughness that could then be used for GDG paths?
I did some more tests with the same settings and mixed the normal glass shader (+inner and outer volume) with other materials, and everything looks more realistic than the standard shader
standardGlass
glass glossy mix (shouldn't the laser be visible here, since it would be GDG paths?)
glass metal mix