normalmap seam trouble on character

JohnnyRaptor

Hi guys

im getting this crappy normalmap seam on the top of the head of this new char im working on. I thought i had it figured out with this other problem i got help with here a few months ago, but BAM now i donno whats going on again...crap!

Zbrush mesh
Normalmap from xnormal 3.17
screenshot from maya 2010 with phong material.

iv done a hard edge where the skull uv splits up...and tried it all smooth, but i still get the seam. any ideas?

JohnnyRaptor

seems to be caused by my unwrap.

it seems if i unwrap so the borders have straight edges, rather than angeled. the problem goes away.

odd indeed as im sure iv seen other peoples similar unwraps without any seams

any thoughts ?

Mark Dygert

Increase edge padding?

JohnnyRaptor

tried everything between xnormals default 16 up to 50 without any change

and the UVs

EarthQuake

Super Happy Cow wrote: »

Think you need to get rid of the hard edge before baking, dude. That helps at high enough angles, but when your shape needs to be smoothed together it will only hurt.

No reason a hard edge would hurt here, unless its split in the cage(projection mesh).

JohnnyRaptor

the seam is from split normals, the mesh is intact, vertices are welded. there is also a seam in the UVs as seen in the previous post.

im not using a projection cage, but the ray distance.

any other tips? i hate it when theres some crap like this that keeps it from being a perfect bake..

i may just resort to performing a dance to please the normal-gods

EarthQuake

Oh i see you are baking in XN, for best display in maya, bake in maya(i would recommend AO in XN tho still). Most likely you'll get seams from normals not being quite in sync between XN and maya.

If you aren't using a cage with averaged normals in XN, the hard edge will also result in a split in the "projection mesh" (cage or not, same concept of "projection mesh"). So softening those normals may fix it.

richithekiller

Hello! Ferg asked me to have a look at this to see if I can help...

I believe Earthquake is on the money when he says to bake the map in maya; the reason being that tangent and binormal data is stored per-vertex in the geometry when you generate a normal map. (This is why a normal map looks wrong if you rotate it even if the uvs are correct) By baking externally in xnormal, this information is not getting applied to the mesh, but it will in maya. Normally (excuse the pun) this isn't a problem, but I think it is the cause of th artefacting you are seeing in this instance. Also, use a soft edge. No need for hard in this example. I'm not 100% clear on this whole issue myself, but give it a punt and see if it makes a difference.

Hope that helps. Good luck.