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Old 03-15-2013, 04:23 AM   #1
serbus
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Self Portrait

I'm looking for help on this self portrait. I finished the sculpting in Zbrush, but when I try to transfer the hi poly normal map to a low poly mesh in Maya it looks really bad.



I've changed the settings to tangent space normals. I've also tried to adjust the bump depth, but it still just looks like a lighter version of the same thing. I've tried rendering the normal map in Zbrush, XNormal, and a photoshop filter with similar results, so I'm guessing there's something up with my settings in Maya

Normal Map rendered in Zbrush


Normal Map rendered in Xnormal


Normal Map rendered in Photoshop


Blend depth reduced


Zbrush rendered Map


Xnormal Map


Photoshop Map


When it comes to texturing and lighting I'm really in the dark here.
 
Old 03-16-2013, 12:23 AM   #2
olivierth
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Xnormal is usually a great way to bake normals. You might have to flip the green channel once in maya (not sure).

Just to make sure, when you are in Xnormal, do you import the high res and the low res mesh?

One thing that troubles me is the part where you tried the photoshop filter. Do you mean with the Nvidia plugin? If so, that plugin in photoshop is mean to go from a bump (black and white) to a normal map. In your case, photoshop is not the place to go.

Also, stay with tangent.
 
Old 03-16-2013, 05:42 AM   #3
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Normal maps will behave differently depending on the application it was baked in and the application that is used to display it. They have to synch with each other so to speak. When you bake in zbrush you can load presets for the target engine, i'm pretty sure maya is there as a preset.

Some general rules...

-Tangent space maps are better suited for characters and objects that move, so use tangent space instead of world space.
-Your low poly, uv map and smoothing groups also play a role in the look / quality of the asset.
-Never use photoshop's basic plugins to create or modify normal maps simply because it won't take into account the low and high poly's normal information. The only tool i'm aware of for photosop that can paint details on normal maps is called Ndo.

Now about the problem, first thing i would try is this:

Take the zbrush map and flip the green channel, this can be done within the maya shader (if you use a real time shader) or material. You could also do it in photoshop, simply click the RGB channels tab, select the green one and invert it. Apply the new map and see if it looks better.
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Old 03-17-2013, 06:10 AM   #4
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Thank you both so much! Flipping the green works perfectly. I'm gonna re-render in zBrush with better settings and I'll post an update shortly.

@olivierth: I was actually using the xNormal plugin for photoshop, but I do also have the Nvidia plugin. I took my AO render and converted that to normals with photoshop. I normally would not use photoshop for 3D normals, but I was mostly trying to determine if my issue were with my normals or with Maya. It didn't really give me the right answer I guess. I did made sure to import the hi poly to the hi poly section in xNormal and the low poly respectively.

@Psyk0: Thank you for those notes, I'm saving them in my archive. I didn't realise that not all normals are created equal. I haven't had the opportunity to use nDo, but some of my classmates have been very enthusiastic about it. I have been looking for a better and more efficient way to texture so its something I may consider investing in if it works for me. Is world space tangent better for immovable objects, like hard surface stuff? Thank you so much for the fix. There are still a couple things off, but I can work with that.


Again, thank you both. I assure you I will never again use free photoshop plugins to render my normals for a 3D model. Also, I want to apologize cause I just realised I should have posted this in the texturing forum and not the modeling forum. >< Doh!
 
Old 03-17-2013, 04:33 PM   #5
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No problem.

I can't recall many games using wolrd space because: they cannot tile easily, they need specific geometry so they can't be re-used easily, mirroring requires special shaders, it's difficult to overlay painted details and they don't compress well. Stick with tangent space unless told otherwise.

Oh and i think your post belongs here too since there's some technical issues involved, plus this section is probably more active than texturing...i think.
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Old 03-22-2013, 06:58 AM   #6
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Here's an update. I'm still working on the lighting, but the normals are looking a hundred times better.

 
Old 03-22-2013, 04:52 PM   #7
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Nicely done.

Quick tip: get rid of black shadows on the skin, if you are overlaying AO on top of the diffuse, change the hue so it doesn't come out as pure black, human skin rarely casts pure black shadows on itself.
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Old 03-23-2013, 10:23 AM   #8
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Yeah, its hard to see in this light, but my shadows are actually a purplish colour. I'll post a render with lighting shortly.
 
Old 03-23-2013, 10:23 AM   #9
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