Lightmap issu in unity

[Mr_Prajapati]

“I am exporting an FBX file to Unity, but there’s an issue. Unity is showing that I need to send a second UV map for the lightmap i

n Blender, but Unity is displaying the first UV map as a texture instead.”

[FedPete]

@Mr_Prajapati

second UV map for the lightmap

What do you mean by ‘lightmap’?

A PBR shader has several input properties ( diffise, glossy, normal … )
Can it be that Unity does this a bit different?

Try building it up in Unity step by step.
In stead of Blender export to Unity. Which are two tool, based on own standards, and the .fbx file is the translator.

[NP5]

Never heard of lightmaps but Blender does make them.
Never been covered in any Blender lecture for GD that I recall, very game specific need?

Found a YT tutorial about them. Only watched a few mins but they do tell of a need for 2 UV maps. SO must be on the lines of what you need.

Bake Lightmap in Blender

[CoreyKnecht]

This is a Unity-specific issue; I remember seeing this message years ago when I was dabbling in the engine. I did some light-… erm, scratch that… I did some basic searching on the issue and arrived at a few things:

• Unity supports up to 8 individual Vector4 UV channels for a given mesh.
  • In default shaders, the first of those channels, UV0, is for texturing, and the second, UV1, is for lightmapping. This error would suggest your mesh has only one UV channel with content.
• It is possible to provide your own lightmap, or you can have Unity generate one. I don’t know how to do either, I’ve simply read that these are things you can do. The point is, it should be possible to fix this in Blender or Unity, depending on exactly what you need.

This page in the manual should give you a better idea of what to do next:

Unity - Manual: Generate lightmap UVs

Maybe somebody in the Unity forums can help you further =)

[bOBaN]

As I wrote on discord… I’m not 100% sure, but don’t use Blender’s UV lightmap algo. It will probably end up with a lot of shading arifacts. Better to use Unity own’s algo for generating lightmap (you can do this after importing your models). When you click on your fbx in Unity, you’ll have this in inspector