Lightmap/Shadow Problems

Development Rendering
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1

For a few days now I’ve been having issues with the shadows and lightmaps in Unreal 4, and seem to have started to occur only recently.

At first I thought it was a problem with the way I set up the UVs for my lightmaps but it seems to be some sort of bug within the program itself. For my static meshes things were set up correctly (as far as I am aware) - second channel is set properly and the UV islands are sufficiently padded. I know this is somewhat acceptable because a few days ago the shadows were absolutely fine.

I later learnt that it must be an issue within the program because the props that are included with Unreal 4 by default are also producing shadows incorrectly.

Here are some pictures to show the problem that is occuring:

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These are some steps I have modelled.

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This is the doorway included in UE4.

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And the door included in UE4.

As you can see the shadows are extremely ugly and fragmented. It’s worth noting that they only show like this once lighting has been built. It happens with every single mesh I place into the scene. I would greatly appreciate some help!

2

Have you tried increasing the lightmap resolution of the floor? If the floor is a bsp, then lower the number higher the resolution. If it is a static mesh, then higher the number, higher the resolution. For bsp you can edit the resolution from the details panel and for static meshes you can do it from either the static mesh editor or the details panel. If you are going to do it through the details panel then make sure you have override lightmap res checked (for static meshes only).

3

Hi Jyates,

HynopticShark is correct. The only thing I will mention as an aside is that when you adjust the Lightmap resolution down for BSP you do not have to do it in powers of 2. I think it defaults to something like 4. If you move it down to a number or two at a time and rebuild you will see marked improvement.

Tim

4

That has helped the problem a lot. Thank you very much for the help. It’s just a case of adjusting the resolutions so I get the look I want.