Seeing no fixes/updates trickling down to 4.26 / master branch of UE4 after 4.26 release, I think it’s safe to say GPU Lightmass is called “done” internally for 4.26 and we might not see anything new/fixed up until UE5. I hope I am wrong, but that’s the feeling I get.
Very likely there will be a 4.27 and possibly 4.28 version before 5 stable, so there’s still a chance for updates.
Hi all,
I have been working on a Lighting Lab scene, trying to test all (or a lot, at least), of lighting capabilities and major situations, to find best practices within a collaborative work. It has been setup for a good quality result, not super-high World Settings, nor not super-high dense lightmaps. I will be sharing it soon, after some more test, and you could make your own tests and/or to complete the scene (or create a new one) to make it more complete and more compromising for certain situations. This way, we will be able to spot weak lighting calculations, and it could be even useful (maybe, I hope), for the Epic’s GPU lighting Team, trying to solve those certain issues.
DOWNLOAD the scene (would be great if you could search for errors, too): Dropbox - Content_GPU_lighting_lab.zip - Simplify your life
On attached images, at left, ‘Old GPU Lighmass’. At right, new built-in 'Epic’s GPU Lightmass:
- Some black seams over the distance (even if pixel streaming is disabled).
- Huge noise over the walls (even with and without denoiser enabled).
- Quite more slow. Over doubled the time, for this two comparison scenarios.
- Not BSP compatible.
- More noticiable seams between modular pieces joints.
- Sometimes, after building, it still says Lighting needs to be rebuilt.
- Sometimes, lighting can pass through 10cm walls and illuminate other walls behind.
- Problems with two sided materials.
- Not working with translucent lighting transmitance.
- Some big squared spots, of different sizes, even at 8192 (maybe because I had Denoiser disabled? But it ‘should’ be probably better, anyway)
IC, FB, without Denoise:
The same, with Denoise:
No IC, no FB, with Denoise:
Maxed out quality (on a 2080 Ti) 3mins, vs 27mins…:
Best regards!
Duplicated, sorry.
picture is not work !
I still saw them :eek:
Anyway I have reuploaded the files. Are they visible now?
Thanks!
I wonder if Epic is reading this thread. This situation with official GPU Lightmass reminds of Cyberpunk 2077.
@virtualHC By chance, do you use WPO in the materials (when blending terrain with the rock mesh) ?
I would definitely make a test case project and submit bug report with it to Epic.
What is left ? old gpu lightmass ? cpu lightmass or real time ray tracing ?
Hi,
As pointed in the message:
On attached images, at left, ‘Old GPU Lighmass’. At right, new built-in 'Epic’s GPU Lightmass:
(All RT effects forced to 0, to avoid having dynamic lighting over there)
i think you use to stationary lights. Change the static and try again. Skylight so change if use static maybe point light work.
All lights were Static. Well, finally, here you are my testing level! The idea could be to make as many GPU lighting builds as you want, but maintaining all the actors unmodified: Dropbox - Content_GPU_lighting_lab.zip - Simplify your life
Let’s compare!
I think with official GPU Lightmass you can only use 128 lights.
Maybe yes. Anyway, there are less than 20 lights on that lighting scene. I meant that you can built the light as many times as you want, trying with different GPU Lightmass parameters, but without changeing the scene! (I dindn’t mean you to place as many lights as you want).
This is the scene: Dropbox - Content_GPU_lighting_lab.zip - Simplify your life
Regards!
@Miguel1900 So I opened your scene and remembered that GPU Lightmass in 4.26 doesn’t support brushes. All those small boxes you hope to get light bouncing off are brushes. Try converting them into static meshes.
Tbh, I feel that GPU LIghtmass is there for a checkbox. Artifacts in the corners of the room in the sample project posted above shouldn’t be there with all the settings cranked up high. Yet, it looks horrible blotchy/blocky. I wouldn’t hold my breath for GPU Lightmass to be usable until maybe UE 5.1 or even later.
For now I’d stick with CPU Lightmass for production.
Of course, I know. That’s the reason there are the same blocks but with static meshes too. It’s a test scene, so I have included all kind of situations I have thought on. Like twso sided materials, emissive materials, translucent materials, BSP and Static Mesh, etc. So they are part of the test itself.
Then, have you tried it with your GPUL and do you get the same weird results?
Thanks!
I don’t think BSP will ever be supported. The rest most likely in UE5.
I used to use it, but it has a lot off issues for me with LODs, terrain and large levels. Plus I got tired of merging non-official GPULM to every new UE4 release (I have to use source UE4, not launcher version). So I am back to CPU Lightmass.
I also wish for a way of more efficiently communicating with Epic regarding the development of GPU Lightmass. On the other hand it might be unfair to compare it to the Cyberpunk 2077 situation since it has never been released claiming it’s a finished system. It’s still considered beta so it’s work in progress.
No, there’s no displacement, only material blending between the RVT grabbed from the floor and the rock textures. The vertex positions remain unchanged by the material. I actually got the same bad results with CPU Lightmass so I’m assuming is a general limitation of RVTs and not specific to GPU Lightmass. I guess this makes this technique (Runtime Virtual Texture based material blending) only usable for dynamic lighting.