Lets make Lightmass EPIC (and understandable)

[Robbie222]

Thank you.

Those are not lighting artifacts. It's antialiasing issue caused by the fact that screenshot doesn't benefit of TXAA, as Heartlessphil discovered.

[MSL]

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.

[MSL]

Can anyone share the lightmass.ini with defaults? Somehow I lost my backup and can't remember all the defaults.

There you go

[Robbie222]

Can anyone share the lightmass.ini with defaults? Somehow I lost my backup and can't remember all the defaults.

[Aljosja84]

Well atleast we know that behind Epic's doors they're working on a solution for us, how exciting! Together with that fact that @DanielW and Koola and Rafael are contributing to this epic discussion we should be hopeful!

[Wilkes]

It doesn't seem like the portals will be ready for general release for some time, as exciting as it would be to be able to use them.

[tupikp]

And the next question would be when this portal will be released? Will this portal be released as part of UE 4.10 or as hot fix for UE 4.9?

[ikifenix]

sorry i am a little bit confused,i know what a portal do,but what is the name of the portal in ue4?is that box reflection capture?

If you are asking to use it, it isn't in ue4 yet, I think that only DanielW (Unreal Engine Developer) has the portals and is teasing us.

[amir.pourshafi]

sorry i am a little bit confused,i know what a portal do,but what is the name of the portal in ue4?is that box reflection capture?

[tupikp]

can any one tell me what are the portals?if they are box reflection capture then i cant understand their effect on lightmass

According to DanielW : "The portals don't change the brightness, they just tell Lightmass where to look closely for lighting. In this case with all the skylight coming in small holes they make a big difference. In a more open scene they wouldn't be any good because the openings to the sky are large."

[amir.pourshafi]

can any one tell me what are the portals?if they are box reflection capture then i cant understand their effect on lightmass

[DanielW]

DanielW portal is the same BoxReflectionCapture?

Just temp icons. The portal is a box, you place it over windows and light entrances.

Also, does uncompressed lightmaps makes a noticeable difference?

It's very noticeable to me esp if you look at a shadow penumbra that should otherwise be smooth.

[tupikp]

@DanielW look very promising. Thank you very much!

[MSL]

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

[heartlessphil]

Do you guys not want to use directional light at all? is there a reason for that?

Also, does uncompressed lightmaps makes a noticeable difference? I have not seen much difference but wondering if with cranked up settings it's better not to compress them...