bartek_zgo wrote: ↑Tue Nov 24, 2020 2:47 pm
So to get the same result I have to map maximum value in exr to 1 and after this apply gamma correction.
You might still not end up with exactly the same result as the LuxCore output, because LuxCore doesn't apply normalisation but a scaling factor that depends on gamma. (Normalisation doesn't really make sense anyways because you would lose control over the image brightness.) You can see the source code fo that factor
here.
If we compute the ratio of this factor for gamma 2.2 and 1.0 we get 0.39.
To demonstrate the impact, I used the "rgb_noGamma.exr" from your scene and processed it in python in two ways to compare with the LuxCore:
First, I normalized the EXR, then applied gamma. Second, I scaled the image by a factor 0.39 as explained above, then applied gamma.
here is the result compared to the direct output from LuxCore:
P.S.: If you're wondering why I use python, that's because I'm used to it and I have good control over the math happening there.
EDIT: This also means I was wrong in my earlier post that LuxCore operates on the normalized image. I assumed that from a quick anaylsis of the first images you posted...