Overlapping UVs?

You need to set your meshes UV layout so that there are no overlapping faces. You can either do that by using a second UV channel, or a single one(still with no overlapping UV’s) if that layout suits your texturing too. And you need to do this in your modeling software.

If you go through the documentation you can find more detailed information on Lightmass and building lights. There are also tons of tutorials on the internet over this subject(mostly on UDK, but the process is the same)

I am new to unreal engine so forgive me for asking such a question.
When I import a mesh (fbx. file) and start building the lighting it shows an error saying about overlapping UVs…

What is this error and what do I need to do to solve it?

It means your UVs are overlapped and it cause some glitches in the baked shadows.To avoid that create a second UV SEt inside your modeling software ( Maya/Max Etc),and be sure to use non overlapped uv layout in this second uvSet.

Thanks for the quick reply

So: Basicly…It means…No tiling???

Heres a few things I have found so far.
4.1 has gotten a bit stricter with lighting…
I have alot of models from my other work that had been working fine in another engine.
They came up with the same thing here as others (Overlapping UV’s).
With alot of studying and reading and testing so I have found the following :

ReImport your models and Double check the Import settings…
One Convex Hull setting got turned on by default on all my models that I had setup in 4.0 after upgrade to 4.1
Import Normals was turned on by default as well

After Generating a Unique UV, it doesn’t set the Light Map coordinate to the New UV map automatically
So generate a UV in the engine means you also need to set the Static Mesh settings->Light Map Coordinate (to your new light map UV)

That fixed quite a few issues…