How to fix the normal map seam?

gametime

so here is the problem:

I modeled my hp arm in zbrush, goZbrush exported it to 3ds max where i fixed the lp and created the uvw map. i send it back to Zbrush and baked the normal map. it baked out fine, but i have an issue with the seams, they are greatly visible and need to be fixed, can anyone help me here?

the problem is visible in 3ds max using xoliulshader2 and in cryengine 3 (although not as intense).

here are 2 images to explain the issue further:






i tried fixing this issue with adding another loop that doesnt effect the tangency, but that didnt work and painting it with the normal blue (128,128,255) makes it less visible, but leaves a grey line.

so i really need help here.

ps: if this is in the wrong sub forum, im sorry

JamesWild

What's on the bottom of that mesh, below the current problem? The way the normals are smoothing it looks like you've capped it but not unwrapped the cap or split it with a smoothing group.

gametime

first of all thanks for the reply. its all one smoothing group. im not sure what u mean by capping it


edit: here is another image of the arm, it might clear things up, dunno

JamesWild

As in is there a hole at the bottom of that object (which I'm guessing is cylindrical) or is it sealed up with polygons?

gametime

ah gotcha. yeah there is a hole at the bottom, but the top is sealed up.

JamesWild

Absolutely sure there's not anything on the bottom there? (even something like a quad loop for the inside of the sleeve) That kind of linearly interpolated darkening just typically only happens when there's an extreme change of direction (>60 degrees) across a smoothed vertex.

gametime

yeah there is another loop like u have drawn. is this destroying the whole seam up to the top?

JamesWild

Just break it off on the UV map and use a smoothing group to break up the rounded lighting.

gametime

to be sure i deleted the whole loop exported it and baked it, but the issue consists

haiddasalami

Out of curiosity why not put the uv seam on the inside of the arm (from arm pit). Would be less noticeable. Also harden the edges of your UV island

gametime

thats because these arms are for first person view and i can hide them best at the backside, but still, the arm can twist quite a bit and the seams might be noticeable.

what do u mean by harden the edges?

haiddasalami

Whoops I think I misread your post, sorry about that. What are you baking in and are you making a cage or are you using ray distance etc?

gametime

im using zbrush to render it, whatever it is using, i dunno tbh, im quite new to zbrush.

almighty_gir

gametime wrote: »

im using zbrush to render it, whatever it is using, i dunno tbh, im quite new to zbrush.

that's the problem right there.

basically, different normal map generating software uses slight variations from each other in the math that is involved in making the map. so as a general rule, if you're baking the map in max, you should render it in max also.

people generally stay away from baking their normalmaps in zbrush for this reason, and either use max, maya, or xnormal.

it's important to note that all three of those use different formulai as well. i'd recommend you doing:

baking in max, rendering in max.
baking in maya, rendering in maya.
baking in xNormal, rendering in UDK.

gametime

great thanks for the info.

ultimately i want to use this in cryengine 3, should i use xnormal for that as well?

respawnrt

http://freesdk.crydev.net/display/SDKDOC3/Polybump use this

mLichy

Put the seam along the actual model seam you sculpted in the Highpoly. Cut in a couple edge edges so it follows that line and bake, then u probably won't even notice it.

Pabs

mind sharing the obj +nm, i want to see if i can find out whats wrong

gametime

alright, at this point i want to thank you all for your help. respawnrt and almighty_gir it seems it works best with polybump (tho it only allows texture sizes up to 2048).

here is what im at now, almost perfect, tho there are these grey shades (see image). idk whats causing them, cause the model has only 1 smoothing group and the normal map seems fine too.


@scapulator: i might later, it seems we almost solved it, tho.

irakli_chkonia

YOU have to change the (color space srgb to color space raw), check the green channel of the texture, and it will help 100%.

it works in blende, painter, maya …