2nd UV channel to work for lightmaps

Graphics Lighting & Global Illumination
1

I have 2 UV channels set up in XSI, but when I export it as an obj or fbx it seems to compress it down to 1 UV channel, whats the best way to work around this?

2

You might have to apply a material that uses each of the UV’s.

As I remember, this created me headaches:
if you create a second uv and you plan to build the lightmap for it in Unity … so you don’t assign a material.

3

okay when I export it and re-import as a fbx it keeps the 2nd channel, but I’m still having issues using the iphone shaders I borrowed from the Penelope game, I don’t know if I named the channels wrong or its not importing right still.

4

I am glad the export worked.

Sorry I don’t know iphone stuff at all. Did you try checking “swap uv” ?

5

Here’s the shader, I don’t know what you mean by swap UV

Shader "iPhone/LightmapOnlyShader"
{
	Properties
	{
		_Color ("Main Color", Color) = (1,1,1,1)
		_MainTex ("Base (RGB)", 2D) = "white" {}
		_LightMap ("Lightmap (RGB)", 2D) = "white" { LightmapMode }
	}

	SubShader
	{
		Pass
		{
			Name "BASE"
			Tags {"LightMode" = "Always"}
	
			BindChannels {
				Bind "Vertex", vertex
				Bind "texcoord1", texcoord0 // lightmap uses 2nd uv
				Bind "texcoord", texcoord1 // main uses 1st uv
			}
			SetTexture [_LightMap] {
				constantColor [_Color]
				combine texture * constant
			}
			SetTexture [_MainTex] {
				combine texture * previous
			}
		}
	}
}
6

There is a “swap UV” on the import

You might also try flipping these to reverse the UV that is applied.

Bind "texcoord1", texcoord0 // lightmap uses 2nd uv 
Bind "texcoord", texcoord1 // main uses 1st uv

This all assumes … that the UV’s are in the wrong order. :slight_smile:

7

Hm, it only looks like 1 UV is working, and swapping isn’t changing anything.

8

Got it working with FBX, its a bit touchy though.

9

XSI fbx export will all time invert your UV channel , so have to remember to swap that when you import.

you can trick that using layer texture in XSI , but hmm this is a bit annoying to do that for every single mesh :smile:

also sometimes export can mess up because you have some cluster kept in your model hierarchy ( which for some completley F*** the export )…

by the way glad you figured out then :wink: