Normal and Displacement Maps

[cgbeige]

The displacement map is meant to be used solo, not in conjunction with the normal map. If you wanted to do that, it would be done like this:

- make a displacement map that uses level 1 as your base and, let's say, level 3 as your target mesh.
- make a normal map that uses level 3 as your base and level 7 as your target.

That way, the displacement will bring up the detail enough to add shape but the normal map can add the detail. But, since normal maps don't affect occlusion, there's not really any benefit to this approach over using a normal map and just exporting level 3 of the mesh. It's overkill.

The best way is to export your displacement map at 16- or 32-bit and make sure that your base mesh level has enough detail to give the overall XYZ shape (remember that displacements are only up and down). Of course, this would all be made easier by the addition of vector displacement maps to ZBrush. That's why they're important.

Normal maps should only be used if you don't care about detail AO (like for a small background object, a game asset that will used baked AO, etc).

[Kinematics]

Hey Cgbeige, thanks so much for your reply as usual! =) Could you clarify the sentence below?

But, since normal maps don't affect occlusion, there's not really any benefit to this approach over using a normal map and just exporting level 3 of the mesh. It's overkill.

Do you mean that since normal maps do not affect occlusion it would be better to just export the mesh at level3? Just a tad confused on that bit.

As for the Noise system in zbrush. Do you know anything about that? Because for example, I have a brick I wish to create. Start of with a simple cube...and subdivide that multiple times, maybe even level 10. If I assign the noise generator and then convert that detail to mesh, there will never be enough detail carried into the polygons.

How do you add the noise and just turn that into a normal map? I'd think it would be good for my model for things like cloth texture etc where I don't need to have ambient occlusion.

[cgbeige]

if you want an incredible amount of detail, you'll have to HD geometry and use noise as a brush modifier:

http://dl.dropbox.com/u/7990437/hdbrushnoise.mov

HD geometry works with map export but not much else. It's sort of half-supported.

As for what I said about AO, I meant that normal maps are best avoided if you're going to use displacements anyway. The only use for them is to fake detail in games. If you are using them in animation that will have an AO pass, just use displacement maps. Look at what the AO looks like for something that uses both a displacement and a normal map:

http://grab.by/grabs/327174177be6ae578bf9d4ec4383b548.png

http://grab.by/grabs/adb5ec56905b73e97bea3ce0ab1520eb.png

If you composited that, it would look wrong.

[Kinematics]

Hey CgBeige, Thanks so much for that insight! I've posted this on the zbrush forums in hopes to see if someone out there has a way. I'll just copy and paste the question here but if it's not possible then I guess what you've suggested is the best way.


Using Surface->Noise Effectively?

Guys, How do you go about using the Tool->Surface->Noise effectively on a 3d model. Say its a simple brick I wish to add noise to. How do I then transfer this to normal maps or displacement maps?

The reason I am having issues doing so is that when applying the Noise. It looks good but upon hitting the "apply to mesh" button, the resolution of the model causes me to loose most of that detail and softens up the noise which gives me a very different result.

I've tried using HD Geometry and then applying the noise but I don't think that is how it really works. Is there a way around this? I've been recommended to use the noise brush....but is there a way using this method?

[cgbeige]

Pixologic needs to make ZBrush a 64-bit app and just do away with the HD geometry hack, since it's so poorly supported (it doesn't work with layers and a bunch of other stuff).

[MagmaPixel]

Agreed 100% Zbrush NEEDS to be 64bit.

Aside from that, Kinematics, If you are unable to get the required amount of noise to transfer at 10 subdivision levels you are surely doing some major closeups. There may be better options outside of Zbrush, for what you want.

-Procedural textures tied to your shaders in Maya, Max, etc.
-Make a tileable noise texture in Photoshop and apply that to your shader.
(You could even layer up multiple noise textures with a layered shader.)

If you create these in grayscale you can apply them as a displacement. It'll show up in your final render.

Edit: Also, if you prefer a normal map, you can turn a grayscale image into a normal map outside of Zbrush, but I haven't done it in years. You'll have to find that on your own.

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