Brice Vandemoortele

Normal Map Reprojection

There's numerous tool out there in various package that allow you to transfer maps from one UV set to another. Unfortunately it never works with normal map and you end up rebaking most of the time. I developed that simple technique that will allow you - just using your lowpoly and a normal map - to transform that normal map from/into world space normal map, rotate and distort UVs, all in realtime.

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The main problem is that the output has no padding, but you can easily recreate those using common photoshop scripts (xNormal has one right?) or even the warp image itself in maya.

If you only need to convert a normal from world space to tangent or the opposite you just need to link twice the same vertex data The shader alternatively allow you to use the normal map with no initial UVs but to generate them on the fly using a tri-planar projection. Especially useful to bake a tiling pattern all over a complex shape.

I used Dmitriy Parkin's awesome model for DWIII, thanks to him you can dl on his website

Released under creative commons by-sa license · 2009

Normal Map Reprojection Tutorial