Luoshuang's GPULightmass

[Muchasty]

@marcClintDion
IMHO Blender Cylces for UE4 is a bad idea - a very bad idea.
Blender Cycles is unbiased renderer and has NO GLOBAL ILLUMINATION ( only AO ).

GPULightmass (and its predecessor CPULightmass) is better for interior as a biased renderer like VRAY with implemented GI.

That is why Cycles gives so many noise on diffuse channel ( only diffuse channel can be compared ) and needs more samples/time to make all clear ( even with current de-nosie alg.).
I used many renderers for interiors like Thea, Octane, Cycles. And I quite them for UE4 cuz of GI ( and one bake -> many shots/video = time saving that UE4 gives ).

BIASED renderer is best for tasks such as interiors.
GPU Lightmass needs only some small fixer like: fixing shadow splotches and maybe a bit improved GI ( or adjustable ) in the matter of brighter bounced rays ( more energy ) to give much brighter interiors if artist needs that. ( I know it is fake but people like it to see that kind of results and it is more like human brain perception (biased gives) that photography (unbiased gives) ).

That is my humble opinion in that case.

[Muchasty]

@marcClintDion
Cylces has not at all of global illumination solver.
This is just a preset that maximizes the amount of light bounces for every ray type

If you enable that preset then your render time should increase drastically.
As I said CYCLES is UBIASED and computes every single ray path.
And that is why it more faithful to reality. It gives no bias to the scene light ( no bias for bounced light).

Typical GI solver works like a mimic of real light bouncing (computation of the surroundings - like light probe in the Blender 2.8 EEVEE ) than computation of every single ray bounce.
That is why GI biased renderer is faster and less noisy than unbiased pathtracer.
But more fake. But most of us like that fake GI

But more professional answer how GI solver works in GPU Lightmass can give Luoshuang

EDIT: Some nice video about rendering methods ( btw: GPU Lightmass uses Radiosity GI ): https://www.youtube.com/watch?v=DtfEVO9Oc3U

[marcClintDion]

Quick question: how is its speed compared to GPULightmass?

I still haven't tried GPULightMass since my experience with UE4 consists almost entirely on logic/gameplay and such, I barely know anything about standard LightMass.

Anyways, here are some screen captures of bakes done with UE4 and Cycles just for your reference.

(i) The first image is stock LightMass, I don't know how to use GPULightMass yet .

(ii) The second image is the raw Cycles bake.

(iii) The final image is Cycles combined with GIMP's Filter->Enhance->Noise Reduction. GIMP is free and open source so using that denoiser code may be an option for you depending on license compatibility.

That Cycles+GIMP image is to me the cleanest but a UE4 expert could quickly clean up the mess I made with LightMass.

The Cycles render takes 2.7 minutes using a 1070.

I'm certain I'll be going for your solution once I figure out how to use it. It looks great, it's fast, and it's integrated into the final destination.

(i) http://pasteall.org/pic/3ff8906b8a30...e279e670e87f89

(ii) http://pasteall.org/pic/8954a25d9a36...79dfbba7921766

(iii) http://pasteall.org/pic/5cf741dd834e...3c9ed21ad87d09

[Luoshuang]

Anyways, here are some screen captures of bakes done with UE4 and Cycles just for your reference.

Did you turn off SSAO when comparing? From my personal experience a path tracer would output 'lighter' corner darkening (I'm not using the term 'AO' here because AO is an approximation to the general path space illumination)

[marcClintDion]

Did you turn off SSAO when comparing?

Thank you, I didn't think of that. I was messing around with indirect lighting to try and brighten up the recessed areas and was just washing out the brighter areas.

http://pasteall.org/pic/719e2680e9f2...d290a2e35f1732

[schauk]

hey guys, i'm facing some interesting issues: the more props i add to my scene, the worse the quality of the lighting gets with gpu lightmass. don't know if it happend prior to 4.20.3, used 4.20.2 before and everything looked fine. one pic is with added props (hidden) and one with deleted props

[Morningcoffee007]

hey guys, i'm facing some interesting issues: the more props i add to my scene, the worse the quality of the lighting gets with gpu lightmass. don't know if it happend prior to 4.20.3, used 4.20.2 before and everything looked fine. one pic is with added props (hidden) and one with deleted props

Did you try unchecking the "compress lightmaps" option?

[schauk]

Did you try unchecking the "compress lightmaps" option?

yep, it is already checked since starting the project. i didn't change anything besides upgrading to 4.20.3 and adding some simple props.

[Situx]

yep, it is already checked since starting the project. i didn't change anything besides upgrading to 4.20.3 and adding some simple props.

Are you sure you are using GPU lightmass? Have you reinstalled it after upgrading? If so, what quality variables are you using?

[schauk]

Are you sure you are using GPU lightmass? Have you reinstalled it after upgrading? If so, what quality variables are you using?

i did ( overwrited the files after upgrading with the unifed ones and made sure the .dll files are allowed.) and yep, im using gpu lightmass, since the gpu batch processing appears and the qualitysettings (preview, medium, production) dont really change a thing. i tried different values in the overwrited lightmass ini.-file ( 32/16, 64/32 and so on) to change the quality, but apart of longer rendertimes it gets only slightly better. as i said, the two shown pictures are the exact same level with same quality, light-settings and lightmap sizes (red in opti-viewmode) but deleted furniture in one pic, so its extremely strange. im using a 1070gtx btw

[chalkgsy]

Just add something on the the issue by Schauk..... I'm about to experiment with this but is it advisable to wait for a 4.20.3 version? Or should the 4.20.2 version work with that?

[pxlntwrk]

Just add something on the the issue by Schauk..... I'm about to experiment with this but is it advisable to wait for a 4.20.3 version? Or should the 4.20.2 version work with that?

GPULightmassIntegration-4.20.2-UnifiedSettings works well here with 4.20.3

[motorsep]

Now we just need 4.21.x support

[AMontali]

Great work on this feature! Will the RTX be supported soon? What about multi-GPU support?

[zeldads]

Great work on this feature! Will the RTX be supported soon? What about multi-GPU support?

It will be great to start by an official support from Epic about the Lightmass GPU... I had a meeting with Epic (Engine tech director and Senior tech art relationship with studios) this week and when I asked about official support they told us it was not in the development plan since they're not supporting new features they don't use on their own games (Because they cannot support fixing issues if they're working everyday with). A little bit sad about that, even if Luoshuang is doing a great job it's complicated to integrate his tools on a pipeline on AAA production if there are no "official" support. But this tool is a time-game-changer, it's making the difference when you have long time about building lighting on dozens levels.