UE4 Lightmap Density Issue.

Apocrs1980

Hello Polycount community,
I am hoping anyone out there can explain what is going on with the light map density on my mesh,
everything else runs pretty much at optimal levels however this one mesh seems to go red no matter what is done to it.
I have done nothing out of the ordinary during it's construction yet it keeps showing as overdrawn.
I've also tried scouring online to see if there is any posts with a similar issue but haven't found any.
Any Ideas??


Thanks for any feed back in advance.

Apocrs1980

Not sure what I just did, But I think there may be a bug in the editor. I had to scaled the model down tiny, export then re-import, then scale it back up and expert and re-import... now it's showing green...it makes no sense.

Obscura

By default, generate lightmap uvs is enabled in the import options, so you possibly overridden your lightmap uv when attempted to reimport the mesh, so now it has different density... 

Anyways, to change lightmap density / resolution per mesh, just open up the mesh with the static mesh editor, and on the right side, properties panel, change the lightmap resolution to a smaller number. As you decrease the number, youll see the density and colorization changing in the lightmap density debug view. You may need to press "apply changes" in the static mesh editor, after changing the lightmap res. 

Apocrs1980

Thanks, did that and it's been reduced, some of the smaller portions of the plant mesh are a light orange, and I changed he density resolution from 64 all the way down to 2 but lighting still gives me an error saying the foliage actor is too dense and wont rebuild.

Any one else run into this issue or have suggestions as how to fix it? I will try and change export options to see if that helps too.

ilari

Is your lightmap coordinate index set correctly? I've run into a very similar looking bug before where the editor forces it to 0, I assume your grass cards are mapped to overlap which explains the high texel density. You can find the coordinate index setting in the static mesh editor and it should be pointing to your lightmap UV set (usually 1).

Apocrs1980

@ilari Thanks man, I ended up making a completely different type of grass geo that is higher in polys but cuts down drastically on the overdraw. Also found the lightmap density option can be toggled on in the foliage tool when the mesh is added to it which brings it back into the blue