Hi there,
Our team is looking to bring our project over to Unity 5 from 4 but we’re having some lightmap related issues. The problem is that Unity 5 seems to be regenerating the lightmap UVs for all our meshes that Unity 4 had generated, which mis-aligns the UVs with our existing lightmaps. Is there any way to bring the project into Unity 5 without it regenerating the lightmap UVs?
I’m quite sure this is the problem because some of our meshes have manually created UVs in channel 2 which are used for lightmaps, and these meshes display correctly in Unity 5.
The lighting system changed in Unity 5. You will need to rebake the lightmaps and probably make changes in order to get back to the desired look. https://docs.unity3d.com/Manual/UpgradeGuide5-BakedDataFormats.html