Huge differences!! between Path+Sobol AND BiDir+Metropolis

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c3kkos
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Huge differences!! between Path+Sobol AND BiDir+Metropolis

Post by c3kkos » Thu Nov 21, 2019 12:44 pm

Hi there, i'm new to Luxcore and, of course, i'm enjoing experiment with settings :D

I attach here 4 images with text explaining the settings used. Just to note the huge differences!

The cycles one differs SO much in color tones! But at the same time is almost identical to Lux's BiDir+Metropolis


The huge difference is in the Path+Sobol.

There are darker reflection areas, and the object's boundaries are more prominent, the "silouette" is very well defined and stronger.
The detail disappointing me, in Path+Sobol, is the hard shadow. It seems unrealistic, compared to the other result.



Just tell me your impressions!

ps1. all the luxcore's are denoised.

ps2. the mesh is 1-click creation with blender stock addon Math meshes under the "Add" category
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c3kkos
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Re: Huge differences!! between Path+Sobol AND BiDir+Metropolis

Post by c3kkos » Thu Nov 21, 2019 3:57 pm

Please download this, i packed all the external data (1 env texture)

Doing so you have the exact scene avalaible for testing against my results.
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Dade
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Re: Huge differences!! between Path+Sobol AND BiDir+Metropolis

Post by Dade » Fri Nov 22, 2019 11:01 am

The difference you are observing is due to the use of Direct Light sampling cache (and the low resolution of the settings you are using). DLS cache is intended to be used in scene with hundreds of light sources and it is not your case so just disable the cache.

You are also using Env. Light sampling cache, it is intended for situation like rooms with few small windows, etc. Again, it is useless in your case so disable it too.

BiDir has also a combined max. path length of 16, while Path tracing has less than half that number. In a scene with subsurface scattering, long paths are useful to improve the quality so I doubled the max. path depth to 16 too.

The result is:

sss.jpg

A lot more in line with the BiDir rendering.
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c3kkos
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Re: Huge differences!! between Path+Sobol AND BiDir+Metropolis

Post by c3kkos » Thu Nov 28, 2019 6:22 am

That explain much.

I feel bad indeed... it's always better to know things prior to use something and clearly this is not my case

read the fu manual!

Hope this will be useful for others.

Many thanks.
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