Global Illumination alternatives

[HavocX]

Just want to say how great this thread is! GI is surely one of the most important features UE4 needs in the coming years.

[Bladerskb]

Would be awesome if someone posted a before/after of a fully fledged demo scene like the suntemple demo inside talked about.
Especially at the very end of the hall with all the flame lights. (supposing it works with point lights), else the day light areas.

Would do it myself but i don't have 4.7 atm.

Again amazing work, seems like we can end up having 4 fully fledged GI solutions by summer time.

[doC]

This looks wonderful.

I think a bit of noise and some imperfections are completely OK (more so if this can get better with years coming due to more hw performance). Not so long ago software renderers in 3d apps have been struggling with AO/GI flickering during animations and so it feels like a game engine should have the privilege not to be perfect

What I wanted to ask is how will these techniques work with characters (deformable meshes). Docs mention a few times that limitation is that it works only with static meshes. Can the DF GI light the characters (without characters "lighting" the environment)? Are there some options, workarounds or complementary techniques in plan that could be used on deformables while the DFGI works on static geometry?

[Midnight640]

i think Dynamic skeletal mesh cubemaps would work for skeletal meshes.
skip to 00:47

[darthviper107]

i think Dynamic skeletal mesh cubemaps would work for skeletal meshes.

UE4 already does something like that for skeletal meshes.

But, it's possible you could use a primitive shape aligned with bones that could be used with the distance fields. Or if you're using a rigid animated object (like a robot) then you could still use distance fields, it would just have to add support for that.

[doC]

So characters are actually able to receive that DFGI? Shapes linked to bones would be for bouncing the light into environment?

Does this DFGI work in the latest 4.7 preview or is it still only in the github source?

[DanielW]

Especially at the very end of the hall with all the flame lights. (supposing it works with point lights)

I haven't added support for point lights yet but it's in the plan.

So characters are actually able to receive that DFGI?

Characters and everything without a distance field representation receive DFGI and DFAO, they just can't bounce light themselves.

Does this DFGI work in the latest 4.7 preview or is it still only in the github source?

Only in github source / future 4.8

[doC]

Would the trick that darthviper107 mentioned regarding shapes attached to characters work out of the box or is that something you will have to add specific support for?

It's great that even without DF characters can receive GI, I think mostly that would even be enough for some time and if the shapes trick would work, that would be really cool.

Great to be watching the progress with reatlime GI while having in mind that just a few years ago software/offline renderers were dealing with similar problems, really amazing it's now something we deal with in realtime applications

[The_Distiller]

I built a little DFGI testscene. It's such a promising approach, keep up the fantastic work Daniel!


Time of day GIF

[Frenetic Pony]

Instanced meshes are fully supported by all distance field lighting methods (AO, GI, shadows) in latest. For foliage you have to go into the instance settings and enable bAffectDistanceFieldLighting. It's off by default because stuff like grass and bushes with high instance counts can really destroy performance.

Well that's what you've got bent normals from SSAO/Ambient occlusion raytraced primitives for right? Or... Crytek changed it to a spherical harmonic occlusion term with even better results, but the same idea.

I am working on landscape GI at this very moment =) My goal is to combine surfel GI with heightfield GI to get a dynamic GI solution for outdoors. It has to be a separate implementation because surfels don't scale up to huge surface area that well, and terrains need to be represented by heightfields instead of distance fields, so a different ray tracing kernel is needed.

Stick with a dynamic cubemap of the sky with multiple taps/importance sampling for that? Usually the sky isn't terribly costly to re-rendering twice.

Compared to LPV here's how I see Distance Field GI:
+ Vastly higher quality indirect shadowing - leaking is actually solvable
+ More detail in color bleeding - material is evaluated per surfel (disk) isntead of for a huge voxel
+ Much higher view distance, not limited by volume texture scaling
- Only single bounce for now (can be improved)
- Have to be able to represent your scene with distance fields / heightfields

Well it's better than representing the scene with a volume texture that can't even have an empty/null representation.

Yeah I haven't done anything for indirect specular yet, and metal is fully specular. I will keep thinking about this. The problem is that one of the expensive steps (irradiance cache interpolation) is already heavy with just interpolating float3 Irradiance, if I try to store directionality which is needed for specular it will get a lot slower. Will probably have to bite the bullet on that anyway.

Here's the paper I mentioned earlier: http://www.jp.square-enix.com/info/l...lumination.pdf Better VPL representation for specular results.

[ZacD]

I'm at a loss here, I can get distance field GI to work in a launched .exe from UE4 4.7 preview 5 by editing the ConsoleVariables.ini file, but no matter what .ini files I try editing, I cannot get distance field GI to work in the editor, help?

[darthviper107]

I don't think it's in Preview 5, you have to do a build from the current source

[iniside]

I'm at a loss here, I can get distance field GI to work in a launched .exe from UE4 4.7 preview 5 by editing the ConsoleVariables.ini file, but no matter what .ini files I try editing, I cannot get distance field GI to work in the editor, help?

You will need to build from master branch.

[ryanjon2040]

Would be awesome if someone posted a before/after of a fully fledged demo scene like the suntemple demo inside talked about.

I'm downloading master branch now. When everything is done i'll post a SunTemple demo video comparing DFGI and LPV.

[ryanjon2040]

Some quick screenshots: