Hiii,
I’ve been searching for a solid answer on this, apologies if it’s treaded ground but I just want to confirm:
I’m getting this horrid ghosting affect Unreal Ghosting Lumen - YouTube
Most visble in smaller spaces, as seen in the video.
First time using Lumen but i think it’s all set up right. Seen a lot of talk about Anti-aliasing but problem is there with and without AA.
Is there something i’m missing or is this just Lumen?
Thanks for any help.
L
Hey there @thelittleparish1! Welcome to the forums! That’s some extreme ghosting. Do you have any form of motion blur in your scene? As you’d already seen, most of the time this issue stems from TSAA or FXAA but if you’d disabled them it may not be the case.
Try disabling this on your SM and see if it mitigates it a bit:
I might also ask what your scalability looks like? Unfortunately, it is only possible to achieve consistant, clean indoor lighting with lumen set to epic at the moment, ghosting tends to be a tradeoff to achieve a higher visual quality with a lesser responsiveness on lower settings.
Heya @SupportiveEntity
Thanks for the response.
Motion Blur is off in Postprocess and project settings. I was excited to try your suggestion of disabling DFL untill i got to it and realised i’d already tried! It was off during the above video.
Hiya @jblackwell engine scaleability was set to Epic for that video. scaled it to low and that got rid of it but, of course, not ideal!
Also to note I tested with a project from scratch and got the same issue.
Any more ideas? I’m wondering if it has something to do with framerate? if it’s an unusally high ammount of ghosting then could it be to do with the freesync on my monitor or something?
cheeers
Hrm, I’ve been trying to replicate that level of ghosting but to no avail so it might be project or hardware specific. I’m not particularly a rendering expert, so I was going to try and tinker with it. I can produce a little ghosting, or a ton with maxed out settings, but still nowhere near your level. I’m going to tinker with what I can for a bit to see if I can think of another fix. Generally whenever I offer the AA fixes and the DFL fix it usually get’s the job done. Might be able to reduce a setting to cut it since scalability kills it, but I’d have to tell which one.
yea strange.
heres a recording of it on the default first person starter content map
ghosting on the bullets is pretty wild…
I’ll muck about with my hardware a bit later today, thanks for your help so far.
That worked with my project and minimized the issue. Thanks.
What does disabling lumen entirely do? Does it solve the problem?
yeah absoutley, swapping to baked lighting gets rid of ghosting entierly so it deff has something to do with Lumen specfically.
Huh, that is really interesting, I’ve been pulling down and testing lumen since EA and that is the first time I’ve ever encountered that phenomena. Normally, lumen error manifests as bubbling, but I’ve never seen this level of ghosting without the normal noise signs.
Our of curiosity, what’s your engine version? Furthermore, might you be able to screenshot your post-process settings?
Normally I only see ghosting like that if lumen is in software mode and can only work off screen space because there’s no good mesh distance fields setup.
Ah yea i’ve got some bubling an noise too, easier to see in the larger spaces.
I’m on 5.0.3
Heres the postprocess settings, lemme know if there’s somin specifc you wanna see.
Heya, i am in software mode, no idea what steps needs to be taken to set-up good mesh distance fields, so i’m all ears if you have further advise!
thanks
Check out the lumen debug vizualizers under view options.
Makes sure static meshes have distance fields enabled and built, and they have enough resolution.
Make sure to avoid any large concave individual meshes, and instead break things up and construct environments in very modular ways.
Hey there, just checking in. How does the lumen debug visualizers look? We might be able to infer something from them if you can show those off.
Docs on how to pull them up here:
hiya,
here you go
Normal:
Global Distance Field:
Mesh Distance Fields:
The walls are only white on the other side… assuming that’s wrong?
Cheers
It looks like you have inadequate distance field representation in lumen-basically, it’s not behaving correctly because the lighting thinks it’s hitting a backface, I believe? It’s somewhat challenging to tell with your scene representation. Are your walls one-sided?
Lumen is a mess I found. I am also having this ghosting, but not as this much. My problem is with illumination when looking through the fire particles the background gets illuminated, despite being in total darkness. They need to fix Lumen, coz as it is it just creates too much weird artifacts.
Ahh yeah it looks like the wall itself isn’t registering with DF. So it could be that your walls mesh normals are reversed, or the wall itself is less than 10cm thick. In your modeling program of choice or even in unreal with the mesh edit tools plugin you can check if the faces are correct, and if it is the case then we might have to see what else can cause your DF not to generate correctly.
In general, even though lumen is a spectacularly powerful system, it has very specific content limitations (especially to scale). Walls have to be manifold, thicker than 10cm (as @SupportiveEntity noted), and simply constructed for the surface cache to know how to parameterize them. Hardware RT will let you fudge a little more, especially with hit lighting, but that is almost always prohibitively expensive.
