A bit of help on getting rid of shadows inaccuracies

Hi there,

I´ve been fighting with this the last weeks and I´m completely unable to solve it, so after exhausting all online sources I could think of, I´m asking here in case someone have some ideas, insight or some tricks I can try, because I really have no clue at all.

I´m posting some pics so you can see the problem. Ok, is fairly common at first sight, but I did tweak the UVs to no result, redid the geometry, put all the objects into an only mesh with a single unwrap, checked the light, checked the lightmap resolution, lightmass settings, and so on.
I am lost.

I´m using Luoshuang multi-bounced mod (which is awesome), light is an Ultradynamic Sky BP (a huge sphere linked with the directional light and skylight, I think that´s how it works) a directional light and a skyLight capturing the scene. There is a box reflection capture, an exponential height fog and a lightmass importance volume (I don´t remember why I put this one in). The geometry I created it on max, simple boxes with quadchamfer for edges, an unwrapp with flatten mapping and then use the plugin on Unreal Tools script to get the lightmaps on the appropiatte channel. Then exported the result as a fbx with Smoothing Groups, TurboSmooth, Triangulate, and Preserve Edge Orientation checked.
The material I checked with and without AO map but it wasn´t that. Not much else there.
Lightmass resolution I went as high as 2048 but still the same.
Lightmass is 0.1 - 4 - 4 - 0.75 for the four main settings. I didn´t change BaseLightmass.ini

Please let me know if you have any idea about what could be causing it. Any help will be welcome.

Thanks!

If you do not use my mod, will the problem gone? I simply want to confirm whether it is directly related to my stuff :slight_smile:

Hi Luoshuang,
I did go back to my old unreallightmass.exe to test if that was related but it turns out the same result. Multi-bounced mod is working great for me!

I found that in my not knowing what the heck to tweak I did change the lightmap channel number so the odd edges and caps of the first image were due to that.
But, still, I don´t have proper shadowing on joints. I might be ok working with this for the video I want to do but it´s really bothering me.

By the way, the directional light is movable because the sun has to go up and down, and the skylight is stationary. Everything else is static. The directional light is using cascade shadow maps.

Here are the last pics after reverting the lightmap channel.

Can you try increasing your texture streaming pool size?

Hit the “`” button, then type r.Streaming.PoolSize 2000

The “2000” figure is up to you really, from what I understand it is related to GPU memory. There is a space between PoolSize and 2000.

Edge bleeding lightmaps could mean there is no padding in uv maps between surfaces with different normals.

Read this article detailing this issue.

Thanks for the answers.
I increased the texture streaming pool size but not when I took those screenshots. It doesn´t affect the problem though. Is there any visible issue with reaching the texture streaming pool size or is just performance related? I didn´t notice any change, visually.

Thanks csimeon, I guessed it was something UV related, but didn´t know how to look for any more sources of knowledge about it.
I will take a look at your link and update the post if I manage to solve it :wink:

I believe if you are using a movable directional light, the problem is not related to Lightmaps, unless you are using other static or stationary lights in the scene. Try setting your SkyLight to movable as well.
There are some options about Shadows (like Bias) in the directional light options that could help.

Otherwise, it appears that could be related to Ambient Occlusion, but i dont know the options to tweak :slight_smile:

Good luck and let us know if you fix the issues :slight_smile:

Hi Bencio,

  • if you have a red comment on screen that your texture streaming pool is over then your light maps will stream. You need to avoid that. - but I only see a small scene. I wonder why it is over.
  • as it is mostly at the bottom of these pillars check if the bottom poly is attached to the side poly in the lightmap uv. Can you show us the uv layout for this pillars?
  • Make sure the lightmap channel is set correctly in the static mesh section and not in the build section of the mesh.

It looks like a lightmap problem.

And sometimes you have to close and reopen the editor after building the lighting to get rid of the texture pool size problem (after saving :wink:

if you use a static skylight then there will be shadows baked from that skylight. It needs to be movable, if your sun moves. Stationary will still bake shadows, afaik and as mentioned before. Only movable lights don’t bake shadows.