Strange shadow striping on Lightmass baked maps.

Hello. I have this issue where Lightmass shadows get this weird striping. The lighting build is made with 512 shadow map resolution. I’m pretty sure the UVs are correct, because I get no bleeding anywhere, and there aren’t any issues with dynamic shadows. However, baking Lightmass returns these shadows. Here are some screenshots along with UVs.

You need to take some time to lay out your lightmap UVs manually. It looks to me like a lot of your scene is only one model. It’s best practice to split your scene up into smaller models for various reasons (culling, modularity, etc) and also for lightmapping. It’s much more efficient to have several small lightmaps as opposed to one giant 512 lightmap.

The issue here is that you’re splitting up flat parts of the model into individual UV islands. You really need to keep floors, walls, and other planar areas each in their own contiguous islands, regardless of how many tris they’re actually made up of. Yes, that means most auto UV tools won’t work, but that’s the price you pay for having nice lightmaps.

They are painstakingly manually made. Oh well. Looks like I’m gonna have to slice the original model in more parts then.

Hi Artistical,

If you’re not familiar with World of Level Design they have have some good tutorials on lightmapping and layouts to explain how to get the best looking shadows.

It’s definitely worth checking out! :slight_smile:

Tim

Thanks for the link, but I’ve followed those tutorials ever since Unreal Engine 3, so UV mapping and the like isn’t new for me. As a matter of fact, the mesh seen in my screenshots is a port from a roughly three times larger one from UE3, which works fine. The striping only happened with this one once I broke it down.

If you’re breaking up the floor into different pieces that will cause striping. You want to break it up to where the walls are separate from the floor, but don’t break up the flat areas themselves. For example, a wall should be one solid piece, but separate from the floor (which is also one solid piece). Another way to put it would be to say break up the pieces wherever there is a sharp angle.