Mr. Lightlove, or how I loved to like the BiDir

Post your tests, experiments and unfinished renderings here.
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FarbigeWelt
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Re: Mr. Lightlove, or how I loved to like the BiDir

Post by FarbigeWelt » Sat Jan 26, 2019 9:45 pm

wasd wrote:
Sat Jan 26, 2019 2:03 am
B.Y.O.B. wrote:
Sat Jan 26, 2019 1:27 am
Why no shadow catcher?
Shadow catcher is offtopic :)
I don't use anything but bidir,
I don't know shadow catcher neither yet.

And as BiDir addict, until a better method arises, maybe a synthesis of CPU smart and GPU brute force shader, which allows similar or even more interesting possibilities of material settings and effects, or the need for a flat image justifies the choice for hires GPU path renders .
:-)
160.8 | 42.8 (10.7) Gfp / Windows 10 Pro, intel i7 4770K@3.5, 32 GB | AMD R9 290x+RX 5700 XT, 4/8 GB
17.3 | 19.0 ( 4.7) Gfp / macOS X 13.6, iMac 27'', 2010, intel i7 870@2.93, 24 GB | ATI Radeon HD 5750, 1 GB
#luxcorerender | Gfp = SFFT Gflops

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FarbigeWelt
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BiDir Today. In the large shadow of Hybrid Path with PGIC

Post by FarbigeWelt » Thu Aug 15, 2019 7:06 pm

A few weeks ago, Dade introduced the new option for the CPU and openCL path render, so called hybrid or back-, forward or light tracking.
Since this introduction BiDir path (Bi-Directional / eye and light path) lost most of common interest. The new option is much faster than BiDir with same or even better quality in a lot of cases. Waiting for the end of a CPU BiDir render is no fun anymore. Too good and too fast is hybrid path openCL+CDPU rendering in combination with pgic for indirect light. One of BiDir's main weakness beside slowness is the lack of reasonably solving specular-diffuse-specular paths. BiDir fails to mirror a scattering light beam, something hybrid path does with ease.

Following and commenting this post here, dark juice, yesterday, I got very curious about how to render correct looking orange juice in a glass in direct sun light. What I have observed during parameter search is quite a long story to tell. Let's begin with BiDir.

Render time for 800*600 picture is between 1 and 4 hours for at least 1000 up to 4000 samples.
Juice CPU BIDir, 1017 samples, ss 0.1, ms 128, ad 0.01, scsc 500, mcr 128, 1h10m.png
Juice CPU BIDir, 1017 samples, ss 0.1, ms 128, ad 0.01, scsc 500, mcr 128, 1h10m
Juice CPU BIDir, 1750 samples, ss 0.001, ms 8192, ad 0.01, scsc 500, 2h30m.png
Juice CPU BIDir, 1750 samples, ss 0.001, ms 8192, ad 0.01, scsc 500, mcr 512, 2h30m
Juice CPU BIDir, 4005 samples, ss 0.1, ms 65536, ad 0.01, scsc 500, mcr 65536, 4h08m.png
Juice CPU BIDir, 4005 samples, ss 0.1, ms 65536, ad 0.01, scsc 500, mcr 65536, 4h08m
EDIT:
Scattering Scale for all three picture is 500.

Abbreviations Key
Heterogeneous Volume ss step size, ms max steps, ad absorption depth, scsc scattering scale
Metropolis mcr max consecutive rejects

Is mcr too small surface scattering of heterogeneous volume is not rendered. There is a difference between mcr 512 and 65536 but not much this means mcr 1024 to 4096 should be enough for this kind of set up.

However, the chosen parameters for the material are obvious a dead end. I required another approach. More about my findings in a next post.
Last edited by FarbigeWelt on Sat Aug 17, 2019 10:48 am, edited 1 time in total.
160.8 | 42.8 (10.7) Gfp / Windows 10 Pro, intel i7 4770K@3.5, 32 GB | AMD R9 290x+RX 5700 XT, 4/8 GB
17.3 | 19.0 ( 4.7) Gfp / macOS X 13.6, iMac 27'', 2010, intel i7 870@2.93, 24 GB | ATI Radeon HD 5750, 1 GB
#luxcorerender | Gfp = SFFT Gflops

wasd
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Re: BiDir Today. In the large shadow of Hybrid Path with PGIC

Post by wasd » Thu Aug 15, 2019 7:38 pm

FarbigeWelt wrote:
Thu Aug 15, 2019 7:06 pm
A few weeks ago, Dade introduced the new option for the CPU and openCL path render, so called hybrid or back-, forward or light tracking.
Since this introduction BiDir path (Bi-Directional / eye and light path) lost most of common interest. The new option is much faster than BiDir with same or even better quality in a lot of cases. Waiting for the end of a CPU BiDir render is no fun anymore. Too good and too fast is hybrid path openCL+CDPU rendering in combination with pgic for indirect light. One of BiDir's main weakness beside slowness is the lack of reasonably solving specular-diffuse-specular paths. BiDir fails to mirror a scattering light beam, something hybrid path does with ease.
Disagree with everything.
Also, there's (almost) no way for luxcore to connect sds paths. So, there's no way to make juice right.
CPU Bidir + Metropolis | Log Power | Core i5-4570

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