Rain v2 Neck Seam

I have Blender 2.93.5 (2021-10-06) and am using Cycles (CPU only) to render scenes with Rain v2.

For a headshot, I noticed a blue-colored seam between the head and neck (top part of image below).

At first I thought this may be due to the textures having bad edges, so filled them in a bit in Photoshop. No change. Finally found that it was one of the SubSurface Scattering nodes, so disconnected it (for head and body material) (middle part of image below).

The blue seam was fixed, but the transition between the neck and body is not smooth. Is this something to do with Phong shading at all (odd angle)? I didn’t see anything obvious when looking at the mesh. But this line is indeed along the cut/seam for the textures. (bottom part of image below).

Sorry for the single image; new member, so can only upload one per post:

The majority of my renders with Rain will be full body, so it’s not crucial to find a fix for this. Still, I’m wondering how to address this for the future.

Thank you.

In case it makes a difference, I’m using an iMac Pro with Radeon Pro Vega 64X.

Looks like they are not connected in edit mode. You can see that kind of error in games where the face has a higher texture map than the body.

Have you checked in edit mode if the verts there are blue or in any colour? Maybe not even connected?

The new subsurf algorithms is causing these things but i didnt know its already in 2.93. Changing from Random walk to the other can also fix it.

Have you checked the other texture maps or try disabling all modifiers?

Seems like head and body are separate, probably due to mismatching number of edges. You can alleviate the issue by data-transferring normals from the body mesh to the head mesh (restricted to the first few edgeloops using a vertex group). It’ll be somewhat costly so I suggest enabling the modifier only for render.

Thank you both for the quick replies. The geo is indeed not connected (I selected a point and moved it):


I’ll read up on your solutions. Thanks!