Which engine wins?
CPU BiDir vs. openCL light path pgic indir cache
285 minutes vs. 10.75 minutes
missing reflections vs. reflections
soft vs. hard
shadow (floor-wall edge)
gloss vs. missing gloss
(corner of chair's back)
3000 vs. 1500
sample (same, low noise level)
Actually both engines lose.
Because both engines cannot render a bright, clean, saturated yellow-slightly orange (behind glass). It is also not clear why the engines render the same scene with different color tones. [EDIT: My setting. BiDir is reddish due to indirect lightening of the faint red ceiling and of one not showed wall. I have tried to eliminate the glass' greenish touch adding softly some red to get more saturated yellow. That obviously failed.]
I guess there is an issue or a limitation of LuxCoreRender's tone mapper
It is okay that objects behind glass look darker but it is wrong if glass with transparency r,g,b 1,1,1 changes hue of together with brightness.
The change of saturation looks as if energy is clamped to some arbitrary maximum and glass absorption is on top of this very wrong energy level leading to not acceptable dirty colors
There are two principles how colors mix: additive and subtractive.
>First happens by adding colored lights (energy adds, result is brighter).
>Second happens by mixing dyed stuff (energy absorption adds, result gets darker).
If one adds a diluted black to yellow one gets olive (respectively dirty yellow).
If one puts on color neutral sun glasses one's view gets darker but not dirtier.
Since this hard-trying-looking-for-clean-bright-yellow-grail-week-end I prefer the engine running 28.5 times faster the rather annoying dirty deep-mud sledge-race in my rig, not only for its speed but also for its polished gloss reflections, despite the nasty shadow exhausted at the white wall's bottom.
160.8 | 42.8 (10.7) Gfp / Windows 10 Pro, intel i7 4770K@3.5, 32 GB | 2 AMD Radeon 5700 XT, 8 GB
17.3 | 19.0 ( 4.7) Gfp / macOS X 13.6, iMac 27'', 2010, intel i7 firstname.lastname@example.org, 24 GB | ATI Radeon HD 5750, 1 GB
#luxcorerender | Gfp = SFFT Gflops