Ambien occlusion mixed with a normal map baking

FourtyNights

This: http://www.zbrushcentral.com/showthread.php?193261-skin-shader-realtime-render-tips

Seems like he is baking AO straight for the low poly with previously baked normal map as an addition for the baking. Without the highpoly.

I tried this, but mental ray doesn't show my baked normals right. I tried inverting red and/or green channels, but something still looks like inverted. I used xNormal for baking the normal map.

Despite the inverted stuff, baked result is interesting.

Has anyone ever tried this before? At least I've never stumbled upon to this in Polycount.

Eric Chadwick

The AO is a separate map, not added to the normal map, if I understand what you're saying.

You say you're using mental ray, but the tutorial uses Toolbag. So your maps will be plugged in differently. Are you rendering in Max, using mental ray? Or are you trying to use the Max viewport? Or something else?

You can bake multiple AO maps and combine them into a better one, depending on your model. For example a cavity map has a tighter range than a traditional occlusion map, so you can get stronger creases, etc.

Another example is if you do exploded bakes, then you'll want to combine one AO baked from the exploded high poly (for fine details), and another one baked from the non-exploded low poly (for the coarser overlaps).

We have some stuff here http://wiki.polycount.com/wiki/Ambient_occlusion_map

Eric Chadwick

Oh and you can actually burn AO down into a normal map, so you have just one texture for both effects. However this is very rare, and it really doesn't look that great.

http://wiki.polycount.com/wiki/Normal_map#Ambient_Occlusion_into_a_Normal_Map

marks

Yeah have fun breaking your lighting by doing that lols

FourtyNights

Yeah, as I rendered my AO with the mental ray with a normal map assigned to the standard material, the result was very close to like baking from high to low. It automatically rendered by reading the normal detail and blended AO with it. Even though the color channels of the normal map didn't display correctly probably because of unsycned tangent basis between xNormal and mental ray. I mean it also got baked wrong because of that.

BUT, finally I found a way to bake ambient occlusion in xNormal from high to low faster, just by setting the antialias to 1x, lol. Drastic improvement with baking time, even though I'm using CPU to calculate it. After that, the mental ray trick was meaningless.

Eric Chadwick

Ah OK, now I understand. You were baking AO from a normal-mapped model. I thought you were mixing the two maps into one.

Which doesn't break lighting btw, it's just a different way to handle things. If your lighting is generally poor (no realtime AO, no SSAO, etc.), and your shaders are setup to handle it, then you can reduce the # of maps and still get AO effects.

Kind of cool anyhow to know it's possible, as it made me more aware of what a normal map can do.