Normal map seams question

Matthew Smith

Okay so I know there is probably an easy fix out there for this but for the life of me I cannot figure it out. I originally baked out my low poly with a cage inside of xNormal and everything turned out okay. In Maya’s viewport it looks like it worked.





But I imported my mesh into Substance Painter to start texturing and this is what I get:





The problem is that I only baked out half of the LP and of course I get a nasty seam down some of the pieces. I didn’t think about this since I’ve never experimented with mirrored UV’s before. Naturally I would like to try and fix this.

I read a thread here which deals with the same issue as I’m having. Theoretically it makes sense but I’m pretty sure I’m just not doing something right. So I duplicated my LP and moved my UV shells one tile to in the negative U.





I then tried rebaking with my entire LP visible with a new cage but I still get that nasty seam down the middle. In fact it looks identical. Is there something I’m missing or nor doing correctly here? Help would be greatly appreciated!

Bartalon

Substance Painter uses -Y swizzle on its normal maps, you can change that in the xNormal settings, or invert the green channel using Photoshop.

If you want to properly view a normal map with a -Y swizzle in Maya, go to your mesh's shape node in the Attribute Editor, find the Tangent Space section, and choose Left Handed.

Zelfit

In Substance Designer 3D view go to shader options and change normal type from DirectX to OpenGL

Matthew Smith

I don't know why I didn't think to try the normal with -Y before but it definitely helped. Here is what it looks like now:



The seam is definitely smaller but still there. I exported using FBX with a hard edge around the UV seam but should I smooth out the whole mesh? It didn't seem to make a difference when I switched to OpenGL either. Could it be from the bake itself? Do I need the cage to be smooth or something? Here are the settings I used for baking the LP as an FBX:



And here are the settings I used to export the cage (it's an SBM format):

seb3d

what´s looking strange to me is that you have shaded uv´s active but both shells shade blue while one should be red with mirrored uv´s. so make sure there are no flipped normals on one half of the mesh.

Matthew Smith

Yea that was my bad on posting that screen cap. I was trying ALL sorts of solutions and that just happened to be the UV set that was up at the time. Right now now I have the mirrored UV in red. I also tried moving it down in the V as well just to see. I even tried just flattening out the areas with the issues to see it would give a smoother transition but I don't even think I notice a difference. I'll keep plugging away and see if I can't fix this...