Lets make Lightmass EPIC (and understandable)

[anonymous_user_af105f5f]

@;411129

Hi All,

I got much better results with following changes:
Static Lighting Level Scale: 1
Num Indirect Lighting Bounces: 50
Indirect Lighting Quality: 2
Indirect Lighting Smoothness: 1

BaseLightMass.ini
[DevOptions.ImportanceTracing]
NumHemisphereSamples=32

[DevOptions.PhotonMapping]
; 400 gives a smooth enough result without requiring a very large search
NumIrradianceCalculationPhotons=800
; Allocating most final gather samples towards importance samples gives a good result as long as there are enough first bounce photons
FinalGatherImportanceSampleFraction=.8
DirectPhotonDensity=700
; Same as DirectPhotonDensity, since currently direct photons are only used to create irradiance photons
DirectIrradiancePhotonDensity=700

[DevOptions.StaticLightingProductionQuality]
NumDirectPhotonsScale=10
; Decrease direct photon search distance so that we will have more accurate shadow transitions. This requires a higher density of direct photons.
DirectPhotonSearchDistanceScale=.2

; Need a lot of indirect photons since we have increased the number of first bounce photons to use for final gathering with NumImportanceSearchPhotonsScale
NumIndirectPhotonsScale=32
NumIndirectIrradiancePhotonsScale=4

My scene has Directional Light apart from Skylight:

I have cranked up Indirect Lighting Intensity to 5 for both.

Most of the artifacts including Light leaks are removed with these settings and Light building times are also at acceptable levels (My scene has lot of complex objects still it took around 50 mins to 1 hours).

Since, I did these experiments with commercial project that I am currently working on, I am not posting screenshots. I will try to post screenshots of Test Level everyone is using here.

P.S: These are not final values, I am still trying to figure out

Screenshots attached.

This is the scene has only sky Light and following settings:

Static Lighting Level Scale : 1
Num Indirect Lighting Bounces : 100
Indirect Lighting Quality : 10
Indirect Lighting Smoothness : 1

BaseLightMass.ini
[DevOptions.ImportanceTracing]
NumHemisphereSamples=32

[DevOptions.PhotonMapping]
; 400 gives a smooth enough result without requiring a very large search
NumIrradianceCalculationPhotons=800
; Allocating most final gather samples towards importance samples gives a good result as long as there are enough first bounce photons
FinalGatherImportanceSampleFraction=.8
DirectPhotonDensity=1000
; Same as DirectPhotonDensity, since currently direct photons are only used to create irradiance photons
DirectIrradiancePhotonDensity=1000
; Need a very high indirect photon density since first bounce photons are used to guide the final gather
IndirectPhotonDensity=2000
IndirectIrradiancePhotonDensity=1500

[DevOptions.StaticLightingProductionQuality]
NumDirectPhotonsScale=10
; Decrease direct photon search distance so that we will have more accurate shadow transitions. This requires a higher density of direct photons.
DirectPhotonSearchDistanceScale=.2

; Need a lot of indirect photons since we have increased the number of first bounce photons to use for final gathering with NumImportanceSearchPhotonsScale
NumIndirectPhotonsScale=32
NumIndirectIrradiancePhotonsScale=4

Strangely, the artifacts at the edges are present only in the screenshots but not in the Editor or in Game play mode.