Best way to composite normal maps on to eachother?

malcolm · Nov 2009

I'm going to composite some high frequency normal map detail on my low frequency normal map that came out of mud box. What is the best technique to do this. Is poops tutorial still valid or is there some new secret way. Also noticed crazybump can composite normals is that good or should I just use photoshop.

EarthQuake · Nov 2009

just clamp the levels to 127 in the blue channel and overlay, nothing more to it than that(i think that is what ben's tut suggests doing).

malcolm · Nov 2009

What about renormalizing the texture and all that junk.

MoP · Nov 2009

Renormalize as a final step. For example I have a script that renormalizes the collapsed layers before saving to TGA.
You don't need to normalize each layer, just the result of all the layers.

XenoKratios · Nov 2009

malcolm wrote: »

What about renormalizing the texture and all that junk.

If you wanna go through the hastle... The idea Earthquake suggested works quite well. Hmm... wait you could re-normalize before you render your textures, couldn't you?

carlo_c · Nov 2009

Here is a thread which explains various ways of doing this and the pro's and con's of each

http://boards.polycount.net/showthread.php?t=66625

From that thread, seems the best bet is to use crazybump to overlay various normal maps

MoP · Nov 2009

XenoKratios wrote: »

If you wanna go through the hastle... The idea Earthquake suggested works quite well. Hmm... wait you could re-normalize before you render your textures, couldn't you?

What do you mean by "re-normalize before you render your textures"? This doesn't make any sense to me.

malcolm · Nov 2009

Okay after reading 3 tutorials all describing the process differently I'm quite confused. Anyone care to post a step by step. Looks like crazy bump is definately for the win in terms of correctness of lighting but then their is an additive method as well which achieves decent results.

JordanW · Nov 2009

Just take your top normal layer, go to it's blue channel, do Image->Adjustments->Levels...->Set the output to 127. Click OK, then set that layer's blend mode to to Overlay.

malcolm · Nov 2009

Thanks JordanW I'll give that a try.

Ryan Clark · Nov 2009

The overlay method seems like a bad hack to me. The result never looks very good.

(But my objectivity is compromised here, so take my thoughts with large grains of salt.)

Source images here: http://crazybump.com/images/composite/

malcolm · Nov 2009

Hey Ryan, I read your comparison thread, which of the hack solutions to you recommend linear dodge(additive)? I'd like to test the photoshop method and the crazybump method and see which one suits my workflow better.

Mongrelman · Nov 2009

I use the photoshop action from one of the project offset guys:

http://www.rodgreen.com/?p=4

metalliandy · Nov 2009

I just had a play with various methods and came up with the same results a Ryan.
The closest i got was using hardlight but its still not as sharp as CB.

All the more reason to make CB a Photoshop plugin eh Ryan? :P

mLichy · Nov 2009

ooooooooooh........ good idea .... but idk if Ryan would do that..

oXYnary · Nov 2009

I can only speak for me, but I tried the xnormal normalize normal map. It ever so slightly posterized the channels, so I would get weird surfacing on curved surfaces. Barely noticeable, but still there. Just overlaying/saving hasn't caused me grief since.

Best way to composite normal maps on to eachother?

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