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🧵 Subsurface-scattering-faux
Anonymous at Sat, 10 Jul 2021 19:27:14 UTC No. 838079
This concerns BDRFs and subsurface scattering.
I will distinguish between realtime-computable BDRFs and BDRFs-raw.
rcBDRF is obtained via cropping formulaic representation of BDRF-raw essentially.
The key idea: Subsurface scattering is obtained through stacking several single-layer BDRFs with the constant infinitesimal depth step. This allows for representation of everyday materials - ENTIRELY WITHOUT the see-through.
Elaboration. There is a certain BDRF formula corresponding to a particular micro-relief. You stack 3 or 4 such kinds of micro-reliefs above each of the others so that the light gets within (microrelief boundaries being semi-transparent).
In other words, typically you obtain the BDRF from a single-layered micro-relief. What if you parallel several with step-constant begetting BDRF formula from exactly the same the reflectance principle?
Again light bounces off the single layer of micro-relief -> typical BDRF formula.
Light bounces just the same off the stack of uniformly stepped similar micro-reliefs -> scatter-faux BDRF formula.
Said formula off the stack of micro-reliefs is bound to be incomparably more monstrous than corresponding single layer's BDRF formula.
Assumption is it however does better represent materials more or less in your room...
Anonymous at Sat, 10 Jul 2021 19:28:30 UTC No. 838080
>>838079
Now. Simplification. I have distinguished between BDRF-raw and rcBDRFs in the beginning.
BDRF-raw's formula COULD be centered around clear-cut an idea forming resulting formula's clear-cut FORMULA KERNEL.
That idea has representation throughout the elucidation in its publication. Including simple reflection off planes and micro-relief of itself.
WHEN YOU STACK MICRO-RELIEFS IDEATIC KERNELS OF THOSE MICRO-RELIEFS ARE THE SAME STACKING AS WELL.
When BDRF-raw's simplified to rcBDRF that KERNEL of resulting formula gets simplified and possibly muddled. STACKING THE SIMPLIFIED MODEL COULD LEAD TO UNSIMPLIFIABLE RESULTS IN THE STACK FORMULA YOU HAVE TO TRACE BACK TO UNREALTIMEABLE ONE WITH THE RATIONALE.
As you stack the micro-reliefs you have to trace that one part of the formula representing stacking of just micro-relief kernels carrying that idea that made paper go.
E V E R Y T H I N G E L S E goes to hell, just the stack of several kernel parts that much survives whatever the cost.
That's scattering-faux. Nevermind.