All actors in my world have this issue. When I move by them or they move it creates this shimmering effect around them as if the lighting is not updating fast enough to deal with the movement. My initial thought was there was an issue with the speed at which Lumen updates because of how Lumen operates when you remove a light from an area very quickly. Any change I make to my Post process volume have no effect on fixing this issue.
How can I fix this or lessen the effects of it?
What quality have you setted in viewport ?
High everything. It happens when I play the game also.
Bump - Still need help with this.
Its Ghosting effect, I think this has more to do with the Anti-Aliasing (TAA) then Lumen, this is one of the downsides of TAA.
You can try changing to MSAA and see if this still exists, Also some materials make the ghosting much worse i.e Translucent materials.
I will look into this. Ill come back and mark your reply as the solution if it works. Thank you for helping me. Very much appreciated.
Alot of us has been requesting SMAA for unreal engine, I don’t know if certain lighting causes TAA ghosting effect to become more apparent (Lumen does contribute to it as well but this has been happening in UE4 as well) but some materials definitely make it worse.
This won’t help with ghosting but will make your scene look a bit sharp. I found those sometime ago during my own Googling into this.
r.Tonemapper.Sharpen 0.65
r.TemporalAACurrentFrameWeight 0.2
r.TemporalAASamples 4
Changing the AA type did not remove the ghosting effect. Not sure how to fix this. Almost every actor suffers from this ghosting effect.
Bump - This issue is still happening. I have searched online and tried many things such as changing AA to MSAA or FXAA but it still does not fix it.
This is a really urgent issue for me as my game is nearly launch and I only just noticed this issue now.
EDIT: The issue happens only when I set the GI to high or greater in the scalability values. AA is not causing the issue.
Bump - Still need help solving this issue.
If lumen is disabled the issue goes away?
Yes it does. If I turn Lumen of in the project settings or in my post process volume then the issue is gone but the lighting is terrible and there are no shadows.
There are no shadows, as in no direct shadows? Lumen is only (for now) an indirect lighting solver, that is a very strange phenomenon.
What mode is lumen set to? Are you operating on Shader Model 5 or 6?
Critically: are your characters somehow rendering as translucent? Lumen struggles with transparency because it can’t write to the depth buffer to denoise them (in my understanding). If your characters are using a nonstandard blend mode, that could definitely cause strange artifacts.
Also, are you using HWRT or SWRT?
If I turn Lumen off then I have no shadows at all.
Lumen Ray Lighting Mode is set to Surface Cache and Software Ray Tracing is set to Global Tracing.
I don’t know what Shader model 5 or 6 are.
I’m using HWRT when available.
I don’t have any translucent materials.
That is extremely strange behavior. Can you share screenshots? I’ve never hear
If you’re using HWRT, then that is in particular confounding. Can you share on/off side by sides for what it looks like with or without lumen?
One thing I notice is that when I first launch the engine the effect is not visible in the viewport. It only becomes apparent after I play the game in the pop-out window.
I also use emissive lighting for all the ceiling lights.
Emissive Material Settings:
I seen that you commented on another thread that I am looking at to try and get some help with this issue.
Here are my post process volume lumen settings:
Lumen On:
Lumen Off:
My walls and ceilings are single faced planes. I thought maybe that could be the issue since they were too thin but the issue happens outside of the walled interior too.
Lumen Project Settings:
Oh, lumen is your only light source?
That would definitely cause some problems then, especially on high. Although this is changing somewhat as the lumen team’s optimizations keep winning perf back, high is generally intended for usable outdoor lighting only. High cuts ray counts and leans more on filtering to get good results; clean indoor lighting requires the Epic setting.
Emissive lighting in lumen is powerful, but it should not be your only source of lighting, especially in indoor scenes and especially on high. That could explain some of your weird ghosting, especially if the emissive is rather bright. I would first try bringing the brightness of the emissive down to about 1/10 of what it is now as a test, and putting a rect or spot light in its’ place, and seeing if that helps.
I’m assuming you have a directional light at least?
Also, for some A/B testing: does the default Unreal Mannequins generate the same ghosting? Does animated foliage?
Also, in case you need to scale perf via using software RT: you’ll want to make sure your meshes are modular (every wall its’ own mesh) and at least 10cm thick, otherwise they’re unlikely to work well with software lumen.
I have no directional light for my indoor scenes. When I have one the light seeps through the corners and edges of the walls.
The emissive lighting comes from the roofs. What can I use in its place? Should I go the static lighting route and bake the lighting instead considering that none of it will be dynamically moved?
The walls are all modular but are single one-sided planes.
Foliage does generate the same ghosting effect.
What do you recommended is the best lighting approach for indoor/outdoor, indoor and outdoor worlds?
NOTE: I removed all my emissive lights from the indoor scenes and the ghosting went away. My main players flashlight does not causes ghosting. Some of the objects in the outdoor level that uses Lumen on high still have ghosting. I also use Ultra Dynamic Sky and Weather.
That may do it, then. Generally, lumen’s best use cases are for modular or destructible worlds and dynamic TOD. If your interior won’t be subject to any TOD, you may be better off just baking it. By your high setting I’m assuming you’re shooting for 60 FPS?
And I would just try a rect light if you can afford it. It can be explicitly sampled, so way less artifacting, and it will scale down better.
If you want to avoid light-leaking, extrude your planes and add some thickness, or put ‘blocker’ geometry around them.
The issue is that lumen is a project-wide setting and you have to live with the results you have in all scenarios. With the look of your outdoor, seemingly open-ish world, lumen can solve that very well. But detailed interior lighting may be more challenging.
What’s your lumen scene visualization for the exterior?
