Hi @The_Distiller is that material using “Default Lit” or “Thin Translucent” shading model?
We recently fixed a bug that caused incorrect shadowing on “Thin Translucent” so this might already be fixed in 5.7 preview.
If you are able to share that test level I can also take a look.
Thanks for reporting that crash. I just submitted a fix for this and it will be included in the 5.7 release.
It’s Default Lit. The translucent shadowing breaks as soon as substrate is enabled for the project in combination with MegaLights.
It reminds me of a bug I reported (and someone replied and followed, but don’t remember his name and he didn’t finnally fixed it, even if scheduled for 5.5 If I’m not wrong) like 1 year ago, where the sun was visible reflecting on translucent surfaces (water) through montains (in Electric Dreams project) when Ray Tracing shadows were enabled. It still happens in 5.7. This might be inherited.
Yes. Confirmed right now with RT shadows, but also with MegaLights enabled in the directional light:
Thanks for the extra info. Are you seeing this issue in 5.6 or 5.7 preview?
Hey everyone,
I’m currently testing Megalight performance and trying to better understand when it actually provides benefits
I’m running tests in an empty level (FPS mode) with various lighting scenarios. However, no matter what I try, Megalight never seems to perform better than having regular (non-megalight) lights.
I’m using default settings everywhere, with Megalight + Virtual Shadow Maps enabled.
My current “roadmap” for when Megalight should help:
When there are more than 100 active dynamic lights in view (rough estimate)
When lights are clustered closely together, not spread apart
When the lights are static (no light functions)
When they don’t cast shadows
Under those conditions, I’d expect Megalight to be beneficial
What I’m seeing in tests:
Many overlapping dynamic lights (4–5 in view): Megalight doesn’t improve performance.
Clustered lights close together: Megalight performs about the same — neither better nor worse.
No shadows Turning off shadows does seem to help Megalight performance.
I might be looking at performance the wrong way (I’m currently testing in PIE mode). Please check my screenshots below.
From this test, 20 lights doesn’t seem to be enough to have megalight. I’ve been testing with also 55,85,175 and 350 spot light with no cast shadow, all clustered together and megalight is always worse. Am i completely missing something ? If all light have cast shadow, then megalight does seem to help but not that by much. If anyone has more insight on performance i would appreciate it
When should we use megalight exactly?
For those of us that used emissive material on hidden mesh to have some low cost light, does it mean that this way of lighting is now not needed with megalight, and instead of hidden emissive mesh we can just use real light ?
I see that “translucency lighting” is now supported in 5.7 Preview, can anyone explain further?
I’m playing around with all the shader models and can’t get any working results. Perhaps it’s because I’m using Substrate?
Having materials like frosted glass behaving properly with Lumen/MegaLights is top of my wishlist currently
I’m noticing a worse than usual shadow terminator problem with megalights when compared to standard raytraced shadows or VSM. This is especially true with screen traces enabled, but the issue exists even with them disabled.
Megalights enabled, screen traces enabled:
Also, any news on colored translucent shadows? I’m wondering if I should bother updating my custom colored translucent shadow method or if I should abandon it.
I have noticed the same issue in my usage of Megalights. Would be nice to have this addressed.
moved my post here, since i think that it’s not MegaLights related
Hey, just wondering, are there any plans to add Vulkan support to MegaLights?
I’ve noticed most projects I test run up to 10% faster when using Vulkan so it would be great to have that supported.
Pretty long thread, maybe somebody already had that issue. I have some serious flickering and sort of dithered shadows from characters ( Third person) when megalight enabled with raytraced shadows on light sources. VSM shadows are alright..
Hi Team,
Just testing 5.7 (non-preview) in Meerkat Demo project. Downloaded, opened, and enabled Megalights for the directional light. Some strange “moving” shadows appear around:
They move when the camera moves, and they don’t correspond to any projecting polygons; are just ghosts. Not only around the character, but around other assets too, like some vegetation.
this shadow looks like the one from the right leg but is overlapping and occluded by the left leg and the rest of the body. hmm…
simple trace i can do in my head.
It could be contact shadows, make sure those are not enabled on the directional light.
(I’d check myself but that’s a big project to download to look at one setting).
They are screen space shadows and can cause artifacts like this.
@glitchered I get your point, but it isn’t. It behaves as described in my post. Here you can see the other leg and its shadow:
@ZacD checked the contact shadows and were disabled. BTW, this is only happening when enabling MegaLights, but working fine with common RT shadows.
Another angle:
this other angle looks like a cached vsm shadow that is not invalidated.
and well… the original screenshot does aswell. didn’t see the right leg there. oops.
how does this look with pure raytraced shadows? just a means to bypass/troubleshoot the vsm cache.
VSMs are not used when MLs enabled, right? Additionally, RT Shadows are enabled too. Same settings, just without enabling MLs (So using RT):
megalights on a directional lamp has 2 modes.
vsm
and raytraced
as you can see… vsm does have some occlusion issues with backfaces. not sure what material settings you need for that, but… that’s something you can investigate and fix. btw… the meercat demo is an older one that didn’t have all the new shaders and techniques. you gotta upgrade and update and fix it. : )
(smooth 5.7 release upgrade, btw. delta patch. cooking some delta shaders. and it just runs : )
