Normal Map Help

WhiteRavenAnim

Heeeeeeewooooooooo! *Rounds everyone up for a group huggle* ^^

Righy-o...I am having some (albeit basic) normal-mapping problems (there's a good chance that I am the problem XD).

I am making a giant...worm...thing. With a freakish spine.

Normal:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/v1norm.jpg
Wire:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/v1wire.jpg

Everything looks happy from the side, but when viewing places where mirroring occurred and where UV seams are...:

Normal (unpainted & lines pointing to problem areas):
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/v2norm.jpg
Wire & flat-shade:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/v2wireandflat.jpg

And pretty much the same issue along the spine:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/v3norm.jpg

A number of things to try to remedy this issue came to mind:

* Ensured that edge-normals were all softened before baking process (and after, post-discovery of this problem).
* Ensured that all face-normals are appropriate.
* All vertices (along the center, mirror-point) are all appropriately aligned, and all vertices are merged. Also, all edges along center-mirror are softened. Ensured there are no gaps; the model is water-tight.
* I do not have an image of my UV layout on-hand to post (I can get it and post later today, but hopefully my problem can be remedied via posting), but I also checked to make sure all UV's were appropriately placed, and were not overlapping one-another.

At this point...I am horribly stumped. My normal-mapping knowledge is limited to a basic understanding of the process of creating one; this is my first attempt at creating one for a model which has symmetry and is mirrored across an axis.

I see that the seaming exists primarily along the center-divide; is it a bad practice to UV/texture-"share" on a normal-mapped piece of geometry? Instead of dividing a model in half and mirroring (half the model occupies one 1024x1024), should the entire model be fully laid out across one map?

Or does the problem potentially lie in my choice of normal map baking preferences? Or possibly my high-quality display performance options? (I should have remembered to jot those down; I'll be sure to gather that information, along with UV layout, for a future post.)

Thank you in for taking the time to read, and thank you in advance for any suggestions!

Drew++

Try flipping(inverting) your green channel in the normal. That looks like that's the problem.

WhiteRavenAnim

Thank you for the reply!

Inverting the green channel basically flipped the location of the problem. In other words, the normal appears (mostly) fine on the origin half, but the seams appear across the mirrored half; after inverting the green channel, the mirrored half appears fine, but the origin half has the seams.

Still, I didn't consider something may have happened with the normal map itself, so the recommendation helped nudge me in a good direction. I'll keep poking and prodding around with channels, and try other methods to fix my edge seams.

Thank you again!

JGcount

I am by no means a nomarl map expert, but could your problem simply be that your normals are flipped on the one half?

How does the "problem areas" look when you use smooth view in maya or whatever package you are using.

Der Hollander

Could you post your normal map? It could be an issue that the map isn't dilated enough and is ending right along the seam. Another thing to try would be to go into the Hypershade and in your file attributes for your normal map, change the filter type from Quadratic (default) to None. Barring that solution, I would strongly suggest that you reunwrap your worm along the edge where the carapace meets the underbelly.
This should solve a lot of your normal issues simply by having a seam that will be barely visible. Eliminate the seams along the middle, and the segmented seams, they're unneccessary and will make your texturing job a nightmare. I guess this would be a response to your earlier question of if the entire model should be on one texture sheet, which it should. Just scale down your UVs to fit. It won't be the most efficient use of space, but will make your model look better.

As a final note, what are you using to make your normal maps?

ErichWK

when I bake duplicated sides, what I tend to do is before the bake, (my friend Hunter Hazen taught me this) duplicate the one side and sew it, soften, (so it's a full asset). And in the UV editor (looks like you are using Maya) use this code on the newer half of the asset

"polyEditUV -relative true -uValue 1 -vValue 0;"

Which sends that uv shell off the 1 to 1 grid. Then send the entire thing through the baking process. I'm terrible with my wording, did that seem confusing to you at all?

Grimmstrom

When you flip a model in half you tend to have to change the smoothing groups so that there not the same as the original half.

Also stupid question but it is welded up right?

bbob

Is the map tangent space or object-space?

WhiteRavenAnim

Thanks for all of the replies; I am greatly appreciative of all of the help!

Unfortunately, I am at work, so I will not have my hands on my images (normal, UV, model, etc) until I get home. When I am, I will gather all of that together for posting, but for now I can most certainly answer some of your questions:

JGcount wrote: »

I am by no means a nomarl map expert, but could your problem simply be that your normals are flipped on the one half?

When I saw the edge seams along my model, my initial reaction was to check numerous things, from face normals, to ensuring that all edges were appropriately softened. Everything was appropriate both before and after the normal map was baked.

JGcount wrote: »

How does the "problem areas" look when you use smooth view in maya or whatever package you are using.

Using default smooth view, with no normal map application (ie, using a default, grey blinn or lambert material), the model appears completely fine.

Der Hollander wrote: »

...what are you using to make your normal maps?

I built a base mesh in Maya, exported it as a .obj for sculpting in zBrush. After sculpting, re-exported back as a .obj to Maya; I then went on to re-topologize my mesh. Finally, I used Render->Transfer Maps in Maya to make the normal map.

(Also, yes, I will get back to you on posting the normal map. ^^)

@ErichWK,

I am indeed using Maya, and no worries about the wording; that was not confuing at all. I will be giving that (and everyone's suggestion, really :P) a shot. ^^

Grimmstrom wrote: »

Also stupid question but it is welded up right?

I might be a little confused as to what you mean, here (and if I am, I apologise).

Do you mean, "are all vertices along the center-divide aligned properly? Are all vertices/edges appropriately merged? Is the model water-tight?"

If so, then yes to all the above; it is one of the things that I checked.

bbob wrote: »

Is the map tangent space or object-space?

I do not remember off the top of my head (and when I get home, I will check to make absolutely sure), but I *think* the map is tangent space.



Thanks again for all of your time and feedback! This has me pretty badly stumped, so I am very grateful for every suggestion. ^^

WhiteRavenAnim

Allrighty, finally getting back to everyone with some more helpful information:

First up, the normal map is tangent space. Also, here is a general breakdown of how/where I split the UV's; the lower/back end is the entirety of the lower section of the map, the upper/mid/torso section occupies the upper-right edge of the map, and all of the head and mouth occupy the upper-left corner of the map. Basically, those are the areas along which the normal-map-seams appear; though mostly only on the mirrored half:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/colsect.jpg

Normal map (1024):
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/normTan.jpg

(Here's what the normal map would have looked like if it was in object space; psychedelic, dood!):
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/normObj.jpg[

UV's:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/UV.jpg

UV's over normal:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/uvOverTan.jpg

Lastly, the result of trying turning on and off Quadratic filtering; there was no visible change in the default, high-quality preview, but there was a subtle change when using the actual renderer...:
http://i59.photobucket.com/albums/g302/StarWhiteRaven/Misc/quadfilt.jpg

WhiteRavenAnim

Well, seems my problem was just my UV's; I should not have tried mirroring normal-map'd geometry.

After fully laying out the UV's, no more issues. /happyface

New normal:


New UV's:






But a few small parts still need some fixing:




Thanks again for all the responses!