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highlight compression
Posted: Sat Feb 20, 2021 5:40 pm
by daros
Hi, I know this has been discussed on blenderartists and that the developers think this should be more of a Blender feature than a luxcore feature, which from a point of view that associates Luxcore exclusively with Blender is correct. However, as some people are now porting Luxcore to other 3D apps like 3dmax, or in our case FELIX rendering, it might, if it's not a huge task, be a good idea to implement some filters of this kind. This would help align Lux's output quality across different apps.
Re: highlight compression
Posted: Sat Feb 20, 2021 5:43 pm
by TAO
Hi, daros.
What type of effects you have on your mind. Can you send a few examples?
Re: highlight compression
Posted: Sat Feb 20, 2021 6:14 pm
by daros
in corona it's called Highlight compression:
https://coronarenderer.freshdesk.com/su ... mpression-
in Maxwell it's called "burn", In rawtherapee and photoshop, again, it's called Highlight Compression.
I don't know if there is a standard math behind. However if i apply highlight compression in Rawtherapee to a linear tonemmapped Luxcore rendering i get something very similar to a Maxwell rendering with a burn turned on.
Luxcore lux-linear tone mapping.
Luxcore lux-linear tone mapping + rawtherapee highlight compression.
Re: highlight compression
Posted: Mon Feb 22, 2021 8:03 am
by TAO
I think in luxCore we already have several parameters for it, maybe B.O.B.Y is the best person to answer this question.
By the way, the Clamp option will do a good job in situations like this.
Re: highlight compression
Posted: Mon Feb 22, 2021 11:35 am
by kintuX
Note:
"Highlight compression" or "Burn" are parameters of
Reinhard tone mapping.
More about it from LuxCore render wiki:
"
Reinhard02 Tonemapper
An implementation of the reinhard tonemapper:
http://www.cmap.polytechnique.fr/~peyre ... raphic.pdf
Automatic."
& Clamping is totally different thing.
But I agree, it would be great to also have manual control over it
Re: highlight compression
Posted: Mon Feb 22, 2021 11:42 am
by TAO
You can find the description on wiki
https://wiki.luxcorerender.org/LuxCore_ ... REINHARD02
Type: TONEMAP_REINHARD02
Property name Property type Default value Description
Code: Select all
film.imagepipelines.<pipeline #>.<plugin #>.type string "TONEMAP_REINHARD02" reinhard tonemapping
film.imagepipelines.<pipeline #>.<plugin #>.prescale float 1.0 reinhard prescale
film.imagepipelines.<pipeline #>.<plugin #>.postscale float 1.2 reinhard postscale
film.imagepipelines.<pipeline #>.<plugin #>.burn float 3.75 reinhard burn
Re: highlight compression
Posted: Mon Feb 22, 2021 4:06 pm
by kintuX
Yes, I know, but what I meant was for its Exposure to also have manual option (like Linear).
Re: highlight compression
Posted: Mon Feb 22, 2021 4:36 pm
by TAO
kintuX wrote: ↑Mon Feb 22, 2021 4:06 pm
Yes, I know, but what I meant was for its Exposure to also have manual option (like Linear).
We have linear too and you can combine as much exposure as you want.
Also, you can have multiple image pipelines too.
For example
Code: Select all
Property(Options.filmPilelines + "0.0.type")("TONEMAP_AUTOLINEAR") <<
Property(Options.filmPilelines + "0.1.type")("GAMMA_CORRECTION") <<
Property(Options.filmPilelines + "0.1.value")(2.2f) <<
Property(Options.filmPilelines + "0.2.type")("TONEMAP_REINHARD02") <<
Property(Options.filmPilelines + "1.0.type")("TONEMAP_AUTOLINEAR") <<
Property(Options.filmPilelines + "1.1.type")("GAMMA_CORRECTION") <<
Property(Options.filmPilelines + "1.1.value")(2.2f)
I add 3 different exposure, etc for the first imagepipleline and 2 for the second one.
You can provide all options or let a few parts be default as i do for TONEMAP_REINHARD02.
Re: highlight compression
Posted: Mon Feb 22, 2021 4:43 pm
by TAO
Is that what you want?
Re: highlight compression
Posted: Mon Feb 22, 2021 4:59 pm
by B.Y.O.B.
The problem with reinhard is that it's auto-adapting to the image brightness, leading to confusing behaviour like described here:
https://wiki.luxcorerender.org/BlendLux ... ng_happens
When I change the brightness of my lamp, nothing happens
You are probably using an automatic tonemapper which adjusts itself to the changed brightness, making it seem like the brightness did not change.
Solution: Use a non-automatic tonemapper (camera settings -> ImagePipeline).
When I make one of my lights brighter, all the other lights get darker (or vice versa)
You are using an automatic tonemapper which tries to keep the image at the same brightness, making it seem like the brightness of the lamps changed.
Solution: Use a non-automatic tonemapper (camera settings -> ImagePipeline).
It also makes it unsuitable for animations.
So reinhard can not be a replacement for highlight compression.