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View Full Version : mirrored norrmal maps in viewport?

rob-beddall
05-05-2006, 02:58 PM
hey,

is there a way to reverse mirrored normal maps in the maya viewport?
let me explain a little...
I've been told that in the unreal3 engine and other next gen engines, you can have overlapping normal maps that are mirrored.
the game engine then does something to the mirrored ones that makes them look as thought they are facing the right way. and not inveresed (right word?)
so anyone know of any plug-ins or anythign at all that (like a model viewer?) that will let me use mirrored normal maps?

hope someone can help...

cheers.
MattBirkett-Smith
05-05-2006, 05:02 PM
This is something I've stumbled across too - very annoying. In my case it was only for bump maps so I was able to assign a different shader to one half and flip the bump depth. For a normal map I guess it won't be so easy. You could try inverting the R + G channels in photoshop and assign a new shader to the other half using this modified normal map but this will probably look a long way off being correct.
_vine_
05-05-2006, 05:19 PM
Funny you should ask that question because I've done that a lot during the project I'm currently working on, and I'm sure a lot of people are asking the same thing.

You'll want to have two materials, one or the positive side and one for the negative. The positive side will have the regular input of the normal map into the materials Normal Camera attribute. The negative material will need a Remap Color Utility node in between the normal map and material. Depending upon your UV orientation, you will have to play with flipping the red and green channels to get the normal map to look correct.

If you use the NormalBump2D nodes from Highend3d to render out your normal mapped models, then plug the Remap Color utility node into the NormalBump2D node which then plugs into the material.

I hope this helps.

I'm trying to work up a Maya-centric document of all of the normal map information I have found in the last two years of using them in a production environment, but there is a lot of information and not a lot of time to write it up.
benclark
05-05-2006, 07:56 PM
I'm trying to work up a Maya-centric document of all of the normal map information I have found in the last two years of using them in a production environment, but there is a lot of information and not a lot of time to write it up.

That would be a godsend. I spent ages sifting through a lot of crap information to get a good normal mapping workflow and I'm still working things out.

There is a lot of quite useless and contradicting information out there. Tutorials generally deal with how to create and apply normal maps but miss things out like Laying UVs out for Normal mapping, dealing with normal map seams, mirroring geometry and UVs etc etc
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05-05-2006, 07:56 PM
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