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Light bounce quality
Posted: Wed Jan 29, 2020 10:37 am
by Sharlybg
Just continue my testing journey . now while trying to see how much brightness/light detail i can get while increase path deph (same number for all diffuse/glossy/specular) :
8
16
64
128
Was now feeling that the Lux RR default parameter to be a bit aggressive. So i wonder how it will turn if can tune this RR setting. Where can i find it ? it is not exposed i think.
Re: Light bounce quality
Posted: Wed Jan 29, 2020 10:45 am
by B.Y.O.B.
The properties are described here:
https://wiki.luxcorerender.org/LuxCore_ ... PATHCPU.22
You're probably looking for "path.russianroulette.depth" and "path.russianroulette.cap".
In the addon, you can add these here for testing:
https://github.com/LuxCoreRender/BlendL ... fig.py#L51
It's easiest to add a hardcoded line, something like
however note that when you change this value, you will have to restart Blender so the change takes effect.
Re: Light bounce quality
Posted: Wed Jan 29, 2020 11:09 am
by Sharlybg
thanks you BYOB for this nice input. going to try this now. Btw i can understand this feature :
path.russianroulette.depth : The path depth where Russian Roulette stars to be used
but this one i don't really catch it :
path.russianroulette.cap : The threshold over which Russian Roulette is used
threshold of what ?
Re: Light bounce quality
Posted: Wed Jan 29, 2020 11:30 am
by Dade
Sharlybg wrote: Wed Jan 29, 2020 11:09 am
but this one i don't really catch it :
path.russianroulette.cap : The threshold over which Russian Roulette is used
threshold of what ?
It is a value between 0.0 and 1.0: higher it is and less likely RR will be applied (1.0 => never applied). It is based on the material luminance: RR applied to small values tends to cause fireflies.
Re: Light bounce quality
Posted: Wed Jan 29, 2020 11:40 am
by Sharlybg
It is a value between 0.0 and 1.0: higher it is and less likely RR will be applied (1.0 => never applied). It is based on the material luminance: RR applied to small values tends to cause fireflies.
it is very well explained thanks you !
Re: Light bounce quality
Posted: Wed Jan 29, 2020 12:16 pm
by Sharlybg
By the way before i change anything in RR default setting here is the light quality difference between
Path+PGI vs Bidir. Note how natural / bright / and progressive is the light from Bidir engine .
Bidir
Pathocl+ Pgi
theses kind of light treatment difference lead to a great realism boost
look the light in the back of the sofa and also light bouncing on the horizontal grid in front behind the second glass.
Re: Light bounce quality
Posted: Wed Jan 29, 2020 12:29 pm
by Sharlybg
It is a value between 0.0 and 1.0: higher it is and less likely RR will be applied (1.0 => never applied). It is based on the material luminance: RR applied to small values tends to cause fireflies.
Btw for simplicity this value can be named ""RR strenght"" while we inverse the behaviour : higher it is and more likely RR will be applied (0.0 => never applied).
More intuitive for artist.
Re: Light bounce quality
Posted: Wed Jan 29, 2020 12:32 pm
by Dade
Sharlybg wrote: Wed Jan 29, 2020 12:16 pm
By the way before i change anything in RR default setting here is the light quality difference between
Path+PGI vs Bidir. Note how natural / bright / and progressive is the light from Bidir engine .
Have you increased the max. photon bounces ?
P.S. BiDir default max. is 16, PGI is 4
Re: Light bounce quality
Posted: Wed Jan 29, 2020 12:34 pm
by Sharlybg
After i add theses lines i can't enable luxcore in blender addon without syntax error :
Code: Select all
# Common properties that should be set regardless of engine configuration.
definitions.update({
"path.russianroulette.cap" = 1,
"path.russianroulette.depth" = 3,
"renderengine.type": luxcore_engine,
"sampler.type": sampler,
"film.width": width,
"film.height": height,
"film.filter.type": filter_type,
"film.filter.width": config.filter_width,
"lightstrategy.type": light_strategy,
"scene.epsilon.min": config.min_epsilon,
"scene.epsilon.max": config.max_epsilon,
Re: Light bounce quality
Posted: Wed Jan 29, 2020 12:38 pm
by Sharlybg
Have you increased the max. photon bounces ?
P.S. BiDir default max. is 16, PGI is 4
Photon deph was set to 40 to avoid any bottleneck :