[For Reference] Path Tracing Only, 64spp for 548 seconds.

[2nd+ Indirect Only] 100K Photons, 100 nearest for estimation. 64spp for 452 seconds.

[Indirect Only] 100K Photons, 100 nearest for estimation. 64spp for 541 seconds. The reason of the refractive sphere quite brighter is that its BSDF may have some bugs, so I uses a fallback, Confusing about why that BSDF works correctly when Path Tracing.

[Direct + Indirect] 100K Photons, 100 nearest for estimation. 64spp for 445 seconds.

Still have some works todo