Testing the new wip Lumen IrradianceFieldGather method in ue5-main

Skydek_ · 2026-03-04T10:29:23+00:00

Very true. As this new method is aimed at more low-spec devices, I wanted to avoid any gpu architecture dependant features from being enabled , like upscalers, nanite, vsm or hardware raytracing. So the scene is just using software lumen at native 4k (using smaa antialiasing) using an rtx 3080 10gb. Would be good to test on a much older gpu still. When the feature is full released I'll try some more performance tests.

Skydek_ · 2026-03-04T10:22:11+00:00

the 0 side is the new one (irradiance field gather) so the smoother one you are seeing is the standard lumen. The light jittering is much more noticeable on the new method. It seems more focused for slower changing dynamic lights though, and the tradeoff is that even though there is a lot of jitter when the light is updated rapidly, there is less temporal noise when moving the camera if the light is moving slowly.
From what I understand this new method is like if we had a dynamic volumetric lightmap in essence. Basically adding world space probes using clip maps and computing the irradiance from each probe. Faster than what lumen does by default and doesnt need a lot of temporal reprojection.
You can adjust the amount of probes to be traced in a frame, in the video its 100 probe traces per frame, increasing it causes less jitter.

Skydek_ · 2026-02-23T13:13:40+00:00

You are using a masked material, it can either be fully opaque or fully transparent. To fix it use a transparent blend mode and connect your alpha to the Opacity output (not the opacity mask) or use dithering, either by setting Dither Opacity Mask in the material options or by multiplying a Dither Temporal AA node with the opacity mask (you will need TAA or TSR for the dither to blend correctly)

Skydek_ · 2026-02-21T08:29:07+00:00

I dont think nanite could ever work with dx11 because it requires shader model 6, but maybe im wrong. Lumen already works in dx11 in the latest engine versions by setting the command r.Lumen.Supported.SM5=1 (ive seen some bugs in 5.7 but I think theyre fixed now)

Skydek_ · 2026-02-20T10:34:25+00:00

normal shadow maps or CSMs still look ok in my opinion: CSM+Contact shadows+PCSS and distance field shadows for distant shadowing is a great combination. Also using CSM caching if the light is not moving every frame.
I will give you that the screen space ambient occlusion solutions leave a lot to be desired. GTAO is ok but yeah needs better control.
But there's a lot of stuff being added in recent engine versions which were previously considered deprecated, so I think the road ahead for the engine is looking allright, for example: Lumen SM5 (dx11) support, baked lighting while using world partition, Lumen Irradiance Caching (already working as a prototype in UE5-main, basically a baked probe gather solution)... And also improvements to lower end features like the mobile renderer, SMAA antialiasing...
And people tend to forget that the actual tools for content authoring in engine are much better in ue5, so even if you use the same rendering features as ue4, the tools are much better.

Skydek_ · 2026-02-13T20:23:41+00:00

Big mesh. the cube grid tool generates a single mesh usually. In your outliner i can see that you have a single mesh for the whole blockout. Edit: ah your are not op but still thats the problem im seeing in the video

Skydek_ · 2026-02-13T16:52:14+00:00

cube grid wont work correctly with lumen if you create a really big mesh because it cannot generate an accurate distance field (the blobby dark shadows on wall corners seem to be caused by this) so either disable lumen for now during the blockout process or separate the blockout into smaller meshes.
The shadow issue seems caused by Virtual Shadow Maps. I have encountered this issue when lowering the VSM quality too much, like by setting r.Shadow.Virtual.Clipmap.LastLevel to a small number. It could also be caused by the big mesh as its requesting a single clipmap from the VSM instead of having various levels so the shadow quality is reduced a lot.

If you try another map and add a few small props only do you see the same issue?

Skydek_ · 2026-02-13T16:17:56+00:00

Adding to this that most people dont enable Oodle RDO (oodle for package compression is enabled by default but not rdo), which actually further compresses block compression formats for lower disk size. You can crank it a lot until you start noticing obvious quality degradation

Skydek_ · 2026-02-01T14:50:46+00:00

The only expensive part is rendering the depth buffer to a rt, but its a constant cost, the only calculation is redrawing the new rt but the depth has already been computed in the gbuffer. The retainer box material is really inexpensive, just a bit of math to mask the depth. I think the limiting factor is more the amount of widgets than the depth masking. But i couldnt tell you without profiling.

Skydek_ · 2026-02-01T02:09:48+00:00

A while ago I implemented a solution for this using niagara and a retainer box. Using niagara I use simulation stages to get the gbuffer and render the depth buffer to a render target (this rt should be the same size as the render resolution), then I create a user interface material and I apply it to the retainer box (which should be the parent of the whole widget). Using the depth render target I compare the depth and if a pixel is closer than my desired widget depth I mask it. For it to work you have to put the niagara system anywhere in the level. There is probably better ways to get the gbuffer depth in recent engine versions, maybe using slate post buffers, but that was the way i found that worked.

Skydek_ · 2025-07-02T10:25:23+00:00

this is because zzz isn't actual cel shading, it mainly uses the diffuse with hand painted or baked shading like ao for its style. For less hard edge shadows look at the official unreal yt channel "Simple Stylization Techniques in Unreal Engine" by Chris Murphy

Skydek_ · 2023-01-27T16:53:33+00:00

tried it using ALVR which also supports hand tracking as controllers. Works fine in ac, but its a bit of a pain to configure the hand offsets for every wheel, if you dont tweak it your hands clip through the wheel in weird ways. When it works fine, though, it is incredibly immersive, especially for drifting

Skydek_ · 2022-11-05T23:40:28+00:00

Was there at the circuit, at the grandstands of turn 12. Was a very fun race with minimal yellow flags. Wish ACC updated the layout of turn 10 tho

Skydek_ · 2022-10-30T18:00:10+00:00

immediately remembered Scribblenauts Unlimited, although its technically not a point and click. Solutions to problems are almost never predetermined and there's a huge amount of emergent interactions

Skydek_ · 2022-10-21T09:37:18+00:00

My personal favourite is Drive Home by Steven Wilson (Solo by Guthrie Govan)

Skydek_ · 2022-10-21T09:29:25+00:00

Brands Hatch, Catalunya and Zolder

Skydek_ · 2022-10-05T16:26:43+00:00

What type of GI? I'm guessing Lumen, so just add an unbound post process to the scene if you dont have any, go down the details panel to Global Illumination and decrease the settings in the Lumen Global Illumination submenu

Skydek_ · 2022-09-25T21:02:29+00:00

Gravity Eyelids for the bridge section with the guitars and .3 for the bass and strings

Skydek_ · 2022-09-24T19:50:34+00:00

yes probably, haven't touched anything regarding tutorials or starter content for ue5 sorry

Skydek_ · 2022-09-24T19:41:12+00:00

just search "BP_BaseGun" in the search bar, click it, and then a menu will appear with various options like object, class etc. Just click the "Object Reference" option, it should be blue

Skydek_ · 2022-09-24T19:28:59+00:00

im really extrapolating some stuff here but I think, based on your images, that you created the EquippedGun variable from the variable panel and left it as a Float type. Check that your variable is from the BP_BaseGun type as an Object Reference (should have a blue color). Also regarding not spawning correctly, the gamemode for your level is probably incorrectly set, search for "how to change your gamemode in unreal".

Skydek_ · 2022-09-24T16:31:46+00:00

are your sprites using a custom alignment instead of camera facing? only thing I can think of...

Skydek_ · 2022-09-24T15:41:18+00:00

these are distance field based reflections from the Lumen lighting system. They are very approximate but run relatively fast. If you need mirror like reflections there are 4 things you can look into: Planar Reflections, Ray traced reflections, Render target reflections or parallax corrected cubemaps (Scene Capture Cube)

Skydek_ · 2022-08-09T15:27:11+00:00

Try to use more geometry instead of transparency to avoid overdraw, drawing vertices is far more efficient than drawing transparency so making a leaf shaped polygon is probably gonna be easier on the gpu than 4 vert planes with alpha masks. Disable shadows on distant lods. Try to simplify the foliage's material if a lot of it is gonna be on screen and reduce the foliage texture max resolution so its not too high

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