I get a weird error and even weirder lightmap bake out of one of my models. The error I get is “Lightmap Uv’S are overlapping by 58.1%, please adjust…”
The thing is, I can check my Lightmap UVs in UnrealED and they are not overlapping! Yet I get this error, even after I let Unreal compute its generic lightmap (instead of using my own). The result is a blobby shadow on the wrong side of my asset. Here’s a picture:
I merged vertices and checked to make sure smoothing groups and everything are ticked on, in export settings. I exported with FBX format 2013. This is the first time I have an odd error of this kind with U4. Maybe the mesh has too many open edges? I can’t really explain where the errors come from. Suggestions, help much appreciated!
No, just 2 channels 0 and 1. I used to have my custom lightmap, but I let Unreal generate one, after I got that error. The thing that makes me wonder why, is that even when Unreal creates it itself (and I can see clearly that they aren’t overlapping, like on the pic I posted), I get the error notification.
>>EDIT<< I completely resolved the problem in the meantime, by deleting the other UV map, making sure geometry and smoothing groups are accurate and clean and creating a new UV-map in Maya. Looks perfect now. Most likely it was an issue of invisible/double vertexes.
I agree with on this one. For instance, your chair (listed in the overlapping error log) will not bode well with using the auto-generated lightmap tool. There are improvements planned that are listed on our Trello UE4 Roadmap, but it’s not going to be as good as a custom layout in your modeling software.
I know you list that you’ve found a solution but I wanted to go over a couple of things that may help you not to have the issues going forward:
If you’re model had the second UV then this is where the engine is looking for the overlapping UV islands. If there is no second UV it will look at the first which is meant to be for your textures.
What modeling software are you using and does it have the ability to check for overlapping faces when your editing your UV?
-> use the in-engine generator just for simple meshes