LuxCoreRender Forums

I'm struggling to get correct SDS reflection on a complex Glass rendering !

Caustic cache is slow and can't catch thoses sds reflection. Bidir also can't . So i wonder if BIDIRVM can do something ? and how to expose it ?

Here is the render vs real image i want to match :
As you can see there are lot of black reflection on the lux one.

It would be good to have the scene.
In general, what you see in glass is the environment - maybe the surroundings just contain these dark areas? How does the environment look like?
I guess you have already made sure that the specular depth is high enough?

Sharlybg wrote: ↑Fri Feb 07, 2020 11:22 am As you can see there are lot of black reflection on the lux one.

I doubt it is SDS related because the scene looks like pure specular bounces to me (it is hard to say without a more general view of the scene). Have you tried to use some really looooooong path depth ?

You are right. i get closer. but really still miss lot of internal reflection compared to real photo.

The real glass probably has a lot of tiny surface imperfections, like small scratches, bumps, dust particles, grease etc. that all catch the light a bit.

not sure if applicable to luxcore but good results...
https://www.youtube.com/watch?v=Sv2wqwsvx-8

... and as noted many, too many times already, LuxCore Glass surface can't do it (multiscattering)!
For an example, make it fully rough and watch it go over to the dark side. Even utilizing WHITE Shadow Color.

A way to hack it - mix, add Arch. Glass to it (the middle one on image below)
NOTE: from the days before Shadow Color option on materials was introduced, tho only for OCL



tho I'm not sure how it works now, haven't tested since

Hi

Sharlybg wrote: ↑Fri Feb 07, 2020 2:12 pm You are right. i get closer. but really still miss lot of internal reflection compared to real photo.

sc.jpg

What did you change to reach this improved result.
What's the exact set up? Is it a glass cylinder with an air helix inside? What do you use as environment lighting?

Where is your reference from?
Thanks for helping to understand the behaviour.

BR

What did you change to reach this improved result.
What's the exact set up? Is it a glass cylinder with an air helix inside? What do you use as environment lighting?

Hi sorry for the late reply. i 've just added a 1/2 sphere dome with some point light shining under it to simulate a brighter env.