http://community.softimage.com/showpost.php?p=11114&postcount=2

[B]Cryrid’s Portfolio and XSI Tutorials[/B]
http://cryrid.com/art

Thank you
Cryrid

Question, does the second uv set has to be different from the first uv set?

I wrote a script that makes a second uv set for you...automatically.....but it basicly just duplicates the existing mesh and drag and drops the current uv set of that mesh into the old mesh and renames it as Light map.

Is not the greatest script on the world, but its something that i did last night, because i had a gazillion of meshes to export for my game project.  Now i just want to make sure if it matters at all.

The only reason i am asking is because on of the tutorials he has two different uv sets. I am not sure if he did this for demostration purposes, or if its because they absolutely cannot math each other.  Which i dont see y not, but just asking..:)

The reason for using a second UV set is so that every face would have a unique UV space for the lighting. Otherwise when it tries to calculate where to bake the shadows it would get conflicting results as one face might have a completely different shadow on it than another.

For example:

(This is just Ambient Occlusion, if one side was dark thanks to an actual cast shadow, they would now all be dark)

So as long as its got two uv sets we all good then?  Awesome!

Thanx for the awesome tutorials by the way! :)