Lightmass: multi-bounced sky lighting

[Luoshuang]

@tonpix;684333

Very impressive light filling and color bouncing improvement. But honestly, I’m not sure what you changed in lightmass binary. Original skylight had only 1 bounce?

Yes. It bounces only once.

[Luoshuang]

@koola;684157

Wow ! This is really really really cool ! Congrats dude !

Hi koola! Waiting for your stunning things!

[Luoshuang]

@LegendreVR;684334

Hey !

That’s some seriously cool stuff there, having more than one bounce on skylights really gives more depth to baked lighting.

I tried to reproduce your lightbleed scene but I can’t quite get similar results with my setup…

This is one of the results I got with a skylight intensity of 3, level scale of 0.1, 5 bounces, indirect quality of 8 and indirect smoothness at 0.75. I am also building lights at medium quality level to decrease bake durations a lot.
I can’t quite find the right setup to have as defined shadows and vibrant colors like in your shots.

What are your lightmass/skylight settings ?

Cheers,
aka LegendreVR

You can download the test scene at: Dropbox - FarshidNaji 4.15.7z - Simplify your life

[rafareis123]

I have tested the latest update. Some conclusions

• The lighting leaks from the Spotlights was fixed. Also the incorrect brightness from bounces.
• The color bleeding mixes the colors more vibrant and correctly
• It’s really faster than the original lightmass, I can say like 20-30%

I did some tests only with the Directional light. Some bugs still persists. I marked it in red to you investigate

[Luoshuang]

@rafareis123;684414

I have tested the latest update. Some conclusions

• The lighting leaks from the Spotlights was fixed. Also the incorrect brightness from bounces.
• The color bleeding mixes the colors more vibrant and correctly
• It’s really faster than the original lightmass, I can say like 20-30%

I did some tests only with the Directional light. Some bugs still persists. I marked it in red to you investigate

Thanks! I’d like to point out that the bright splotches are caused by insufficient irradiance photons. This is the downside of my temporary fix to spotlights, because it turns off indirect path driven photon emission, then the efficiency of irradiance photons goes down.

There are two ways to fix this:

1. You can raise “IndirectIrradiancePhotonDensity” in BaseLightmass.ini to increase the number of irradiance photons. This will increase the time of “calculate irradiance photons”.
2. I’ll investigate whether it is good to let directional lights also use the radiosity-like techique.

Edit: If the splotches appear as the first bounce of directional lights, then you may also want to change “CachedIrradiancePhotonDownsampleFactor” from 2 to 1. This is another drawback of the radiosity-like technique - the lightmap resolution affects not only the resolution of light it receives, but also the light bounces from it. If the downsample factor does not work well, then you may have to increase the lightmap resolution for the objects that are bouncing light.

[Norman3D]

@;684427

Thanks! I’d like to point out that the bright splotches are caused by insufficient irradiance photons. This is the downside of my temporary fix to spotlights, because it turns off indirect path driven photon emission, then the efficiency of irradiance photons goes down.

There are two ways to fix this:

1. You can raise “IndirectIrradiancePhotonDensity” in BaseLightmass.ini to increase the number of irradiance photons. This will increase the time of “calculate irradiance photons”.
2. I’ll investigate whether it is good to let directional lights also use the radiosity-like techique.

Man… I can’t thank you enough for your work! This is very exciting!

[BMY-A]

4.14 version can be used

[anonymous_user_21e38222]

@;684400

You can download the test scene at: Dropbox - FarshidNaji 4.15.7z - Simplify your life

Thanks for sharing, I’ll have a look at how you configured everything.

EDIT : well, its was only a matter of tweaking auto exposure, which was disabled in our test project !

[Daedalus51]

This is insanely awesome! Thank you so much for your effort! So I can just drop your lightmass exe over mine and then it works? Also, I just installed the hotfix for 4.15 but that should not change anything, right?

God I hope we can make this default in Unreal as soon as possible. Its great to see that is already having a peek at this so fingers crossed!

I would love to have this as part of my setup, but since I am also doing the lighting academy, I have to keep a clean UE4 version so people can follow along and dont have to install modifications…so yeah…just again: PLS Epic, pick this up and implement it

Cheers and big thanks!

[Wilkes]

@, you should mention this in your next video. This deserves as much attention as possible!

[Luoshuang]

@;685218

This is insanely awesome! Thank you so much for your effort! So I can just drop your lightmass exe over mine and then it works? Also, I just installed the hotfix for 4.15 but that should not change anything, right?

God I hope we can make this default in Unreal as soon as possible. Its great to see that is already having a peek at this so fingers crossed!

I would love to have this as part of my setup, but since I am also doing the lighting academy, I have to keep a clean UE4 version so people can follow along and dont have to install modifications…so yeah…just again: PLS Epic, pick this up and implement it

Cheers and big thanks!

If you had replaced UnrealLightmass.exe then installed 4.15.1, it would be overwritten by official version, so you have to replace it again. has been busy implementing some volumetric lighting/fog feature for 4.16 (checkout: https://github.com/EpicGames/UnrealEngine/commit/2826204161186f948cca2061f89d41febc31e723)

[rafareis123]

I did some tests from this old scene. I forced the lighting temperature colors to potentialize the scene mood and the color bleeding. The scene has 15 lights (skylight, spotlights and pointlights) and it was built in 3 hours… pretty fast compared to it old lighting setup. I have raised the number of photons/samples a lot but some bugs still persists.

[Luoshuang]

@rafareis123;686550

I did some tests from this old scene. I forced the lighting temperature colors to potentialize the scene mood and the color bleeding. The scene has 15 lights (skylight, spotlights and pointlights) and it was built in 3 hours… pretty fast compared to it old lighting setup. I have raised the number of photons/samples a lot but some bugs still persists.

Hi =)

Are you referring to these not-so-smooth lighting transitions on the ceiling/walls?

If so, then unfortunately you have to decrease either “Static Lighting Level Scale” in the editor or “RecordRadiusScale” in BaseLightmass.ini (RecordRadiusScale has different configuration in different quality level, so make sure you change the one you use)
Unfortunately both of them will lead to longer build time.

[BMY-A]

Look at the curtain material, can you?

@rafareis123;686550

I did some tests from this old scene. I forced the lighting temperature colors to potentialize the scene mood and the color bleeding. The scene has 15 lights (skylight, spotlights and pointlights) and it was built in 3 hours… pretty fast compared to it old lighting setup. I have raised the number of photons/samples a lot but some bugs still persists.

Look at the curtain material, can you?

[Pixelpirates]

This looks absolutely incredible, thank you =D

[Luos (Luos_83)]

I know its completely offtopic…

But its so odd to see a name that has the same first four letters as mine.

[anonymous_user_7ea5c0e9]

Hi everyone,

Here is a test we did on one of our last project.

UNREAL ENGINE ARCHITECTURAL VISUALIZATION - LIGHTING SCENARIOS (PART 1)

The improvement in terms of light quality is amazing … congratulations for your work !!!
We have 3 different lighting scenarios in this vidéo.
The difference, compares to the “one bounce” method, is really obvious for the night versions of the lighting.
It’s sooooo cool to be able to create a soft light so easily.
There is still some bugs in our lightmaps in this version.
We will try to increase the indirect lighting quality and calculate another one in order to see what happens.

Sorry for the crappy transitions between the different lighting scenarios … we not blueprint’s ninjas

The rendering time is really acceptable I think.

I have one question : the “Indirect Lighting Intensity” (in Skylight’s detail panel) doesn’t seems to affect the calculation.
Is it a bug from Unreal or maybe something you didn’t implement yet ?

Once again, congratulations for your work !
Cheers

The Obvioo’s team

[anonymous_user_1ff6bdf6]

Hi guys,

I tried this “lightmass.exe”, the result is fine, really. The lighting is more "homogeneous’.
But the build time are very, very, very long ( 1h VS 5-6 hours )

two questions :

• How to set the bouce number ? Where is the parameter ?

• How do you handle the lighting test with this render time ? it’s very long, and I don’t know how you can do many light test.

thanks,

A.

[Faceless]

I too would like clarification on where the Bounce setting is - does it just pull from whatever number you have in World Settings->Lightmass → Num Indirect Lighting Bounces ? Makes sense if that is the case, just curious… At any rate, awesome work buddy!

[ZacD]

It is the same Num Indirect Lighting Bounces setting.