Mustard colour on lightmap density viewmode

I’m often getting this hard to read mustard colour on my assets.

1)What does it mean? Too high or too low?
2)Sometimes if I change LM resolution in asset properties it changes the colour in lightmap density in the viewport. Yet when I get this mustard colour it only changes after I’ve baked it.

Any ideas what could be going on here please?

I wouldn’t worry about the lightmap density viewmode, just look at the mesh and if the shadows look good then it’s fine. The only thing to consider then is whether you might get away with a lower lightmap resolution.

Here is that mustard thing that happens before bakes. Even at a lightmap resolution of 4096 (2048 now) it still appears green and blue. Now I know these are bad UVs but what else can you do? I know that I will be continuing to evolve this room so I don’t want to spend time adjusting and changing the UVs everytime I change the room. My hope was just to do a quick unwrap and give it a high resolution, then later when I’m happy with the final room I’ll map it well and hopefully get away with lowering the resolution.


You’re much better off mapping it properly to begin with, and avoiding using UE’s internal un-wrapper. It got some upgrades, but it’s still not as good as doing it yourself.

The UV’s will change drastically depending on how it’s mapped, AND the resolution you use. Things need to be mapped sensibly, and islands arranged as close to the 3D model as possible. This will help when using lower resolutions.

Again, don’t worry about the visualizer, as long as it looks fine then it’s OK.

But–in your case you’ve got a very large amount of surface area in a single mesh, and that’s not going to get a good enough lightmap detail. For me with that type of thing, the ceiling is at least it’s own mesh, along with the floor and the walls, if that’s not high enough resolution then you then have to split each of those up further. For instance I did a model of our office and had a floor piece for each room and something like 8 wall pieces.

So it’s better to use 4 x 512 lightmaps for a room than say 1 x 2048 lightmap?

I’m not sure about the technical memory issues, but the issue would be that there’s a size limit on lightmaps, so if the highest resolution isn’t good enough, then you need to split it up so that together it equals an even higher resolution.

Technically yes, because it’s quicker to load them in and out of memory and you can unload the ones that aren’t on the screen. Depends on the situation though, there’s never one answer for these things!

You’ve probably imported the mesh as a static mesh, or set the blueprint the mesh is in as movable. These objects do not get calculated in the light bake because they could move.

That Bump…

Hello. Now I got the same problem with the scene. How did you fix it?

The lighting quality is quite bed