ZBrushCentral

normal map seam troubles

ZBrush Usage Questions
#1

hello!
I have some troubles… of course I already serach the forum, but I have difficulties to follow conversations.
I modelled a dragon under 3ds max 9, unwrapped it’s UV under maw 9, reset Xform (and blabla…)
imported it in zbrush (in 3ds format) sculpted it, ask Zmapper to calculate a normal map with some 3ds max 8 preconfig, then I exported in PSD format, and use it on the base mesh.
I fixed seams before calculate normal map but I still have problems… is it due to max9?

#2

You have explained what you have done, But what problem are you facing with the normal map

#3

héhé! hum…
I have problems with seams: on the body, the normals colors are not the same at seams, and I see much seams, and like a picture is best than 1000 words:



#4

Try adjusting the “seam overpaint” and “on UV seam” values to get a clean normal map.
[NORMALMAP.jpg](javascript:zb_insimg(‘76848’,‘NORMALMAP.jpg’,1,0))

#5

well it don’t works, I still have different colors at 2 sides of belly seams.
another idea?

#6

What’s happening with your normal map is typical of Object Space maps. In fact, it’s inherent in them. They way that they are calculated (whether using ZMapper or some other program) results in a flipping effect every time you cross a UV seam. This means that GUVTiles and AUVTiles mapping methods are not good for Object Space maps.

The only way to avoid this is to use Tangent Space maps instead.

If that’s not an option, the workaround is to use a different UV mapping where you hide the seams in places that won’t be visible.

#7

I have been facing the same problem in the seams,I use tangent space normal to get my normal done.It only worked once but i dint notice the setting that time.I have been trying to get the same setting but i cant figure it out.

There is a workaround you can try using Xnormal http://www.xnormal.net/

It gives you a normal map without any seams.

#8

I still have the problem…
And now I think about it, I think the problem comes from max…
cause when I import a 3D model from Zbrush, UVs are cutted, and it makes plenty of lines like this… I have just to weld it for it disapear… but now I have my uvs I won’t remake it symatrical just for this…
I’ll never could do only one UV piece…

#9

That certainly looks tangent space, the problem seems to be the fact the seams are located on sharp boundaries, at least the angle at the belly mid-line may be a little severe. There should be an option in zmapper to help this… check you have smooth normals active. Otherwise look at bevelling that edge and using the zmapper projection option with the new mesh?

#10

well I really tryed many things with Zmapper.
but I thing this is max wich don’t make link with normal maps, if I brak some UVs under max this will create the same problem…

#11

I have an idea, if you are using Max, then try the smooth modifier, and set the threshold until the poly’s either side of that edge have the same smoothing group (or do it manually). The verts on that edge need to have continuous normals to avoid seams, if you have any ‘sharp’ edges (where there is a change in smoothing group) then the verts on that edge will have multiple normals, which won’t be pointing in the same direction. You can see how this could lead to a problem like yours! I would even suggest you put all poly’s in the same smoothing group since there are probably no edges you want to maintain as ‘hard edges’ in your mesh anyway…
good luck!

#12

well it changes nothing…
moreover my smooth groups was already the same everywhere. :cry:

however thank you all!
if somebody have another idea…

#13

hello!
I have no so problem than before, it just remains that 3ds max don’t make links between seams… Dos somebody can help me?

#14

I relaunch this post cause I NEED a solution.

I have the same matter in max, maya and torque engine!
I have absolutly no matter in UVs, normals, mesh, so it comes from Zbrush…

here is some screen to remind you the seam broke in normal maps:

[http://img199.imageshack.us/img199/4021/nmatterscreen.jpg
it renders:
[url=“http://img36.imageshack.us/img36/7594/nmatterrender.jpg”]http://img36.imageshack.us/img36/7594/nmatterrender.jpg

notice this is NOT a symmetry matter, cause the back is OK, not the shoulder.

here is the belly seam:
[url=“http://img190.imageshack.us/img190/1161/nmatterrender2.jpg”]http://img190.imageshack.us/img190/1161/nmatterrender2.jpg

here is what happend under Maya: the same thing!
[url=“http://img190.imageshack.us/img190/6629/rat3p.jpg”]http://img190.imageshack.us/img190/6629/rat3p.jpg

here is my CLEAN UVs (no inverted UVs, no double UVs…)
[url=“http://img38.imageshack.us/img38/1717/ratuvs.jpg”]http://img38.imageshack.us/img38/1717/ratuvs.jpg](http://img199.imageshack.us/img199/4021/nmatterscreen.jpg)
no hole in mesh, not a renderer matter, not a computer matter, not a soft matter, not a face normal, smooth group, bug, double, inverted face, UVs nothing of alll this…

and the normal maps render like in maya and max in torque engine.

any idea, please?

I would be gratefull, If I could use zbrush to create this bad rat.

#15

the problem is coming from your UVs as far as I can tell. try to keep things on a vertical or horizontal. it also seems that you are using mirror UV’s in some areas, this can cause problems with seams as well. having a perfectly vertical or horizontal seam edge will fix those problems.

the problem comes from how a normal map is read by the render engine.
red is left/right, green is up/down, and blue is forward/back.

have you tried using a different method to generate the normals? MAYA, xNormal, etc?

hope this helps
[UV-setup.jpg](javascript:zb_insimg(‘141488’,‘UV-setup.jpg’,1,0))

Also, organic models will almost always have a seam. The real trick is knowing how to hide them. If you look at the Gears of War character models you can find seams on them as well…so don’t fret if you can’t get rid of them all.

#16

how… nice tips!

a french forum adviced me to test Xnormal, I’m getting it right now.
trying it uunder maya would kill the autodesk soft! XD

mmm, If I have to modify my UVs, can I take bake my high resolution mesh I already madeunder Zbrush with old UVs?

that’s however very nice to know that I’ll certainly always have some problems with seams.

#17

OK, I succeded to reduce it by modifying UVs! =)

thankyou so much!!!

#18

derkomai, can you explain how you modified the UV so to reduce the problem?
I 'm having the same problem, and can’t get any solution…Thanks.

#19

Same Here… I have been having the same problem. Can you post images of your UVs Before and After?

#20

OK, like goast666 said me, it isn’t possible to get rid of this problem.

hheey yes, we are in 2009, this is technology!

here is my old UVs:
http://img38.imageshack.us/img38/1717/ratuvs.jpg

and the new ones:
<A href=“http://img36.imageshack.us/my.php?image=uvs.jpg” target=_blank>http://img36.imageshack.us/img36/2085/uvs.jpg

softs only make correct links between horizontals and verticals, so I make the link between shoulders and back as best that I could.