G8F skin seams visible when accentuating glossy and topcoat settings?

RenderPretender

Please see subject line. I'm using the following method to create an oily skin look, without the shell or condensation maps:

https://thinkdrawart.com/how-to-get-wet-skin-in-iray

It yields a generally pleasing result, but the G8F skin texture seams are accentuated with a sharp line, necessitating postwork. UV is correct. Anyone know of any other remedies for this issue?

NorthOf45

Check for consistent values for Normal, Displacement, and Bump maps, if used, on all the skin surfaces. Dial them out completely to see if that removes the line, then add some of each to see if you can match the seams. Make sure that all the "wet look" parameters are the same for all the skin surfaces, too. (Use the "Skin" group on the Surfaces tab as a shortcut to select them all).

RenderPretender

NorthOf45 said:

Check for consistent values for Normal, Displacement, and Bump maps, if used, on all the skin surfaces. Dial them out completely to see if that removes the line, then add some of each to see if you can match the seams. Make sure that all the "wet look" parameters are the same for all the skin surfaces, too. (Use the "Skin" group on the Surfaces tab as a shortcut to select them all).

I used the skin/lips/nails group to select them all because all of those things would be oily in a real-world beach scene. They all have identical values as in the referenced settings (see link). There are no normal or displacement maps in the skin, but the arms, torso, and legs all have the same bump map settings and topcoat/glossy settings. I can't figure out where the variance is coming from. I'm just HDRI outdoor lighting, so maybe it's acccentuating something at certain angles because it's only visible on the model in certain scenes, but it seems that the way that the individual skin texture zones reflect light is not contiguous across the seams.

NorthOf45

Do all seams show this effect, or only certain ones, like between the face and torso, or torso and leg, etc.? Is this a thin line along a seam or a different skin tone from one surface to the next? Is it a horizontal gap, like a space between surfaces, or a difference in height? Try a spot render up close (real close), tangential to the surface to see any difference in height and/or any gaps between surfaces at the seams. Bump maps don't physically displace the mesh, but they do mimic surface details so the shader might be picking up something. The resolution is different for different surfaces, so maybe they need different bump settings. The bitmaps might all be 4K, but the face, for example, is a lot smaller than the torso, so it gets more detail per square inch of bitmap.

Try the process on another figure or texture set to see if it gives the same results. (Hint: you can save only the wet look parameters as a material preset, just deslect all other settings when saving, then you can quickly apply it to any figure instead of dialing it in every time).

If anyone else has any ideas, feel free to jump in. AFK for a while...

RenderPretender

NorthOf45 said:

Do all seams show this effect, or only certain ones, like between the face and torso, or torso and leg, etc.? Is this a thin line along a seam or a different skin tone from one surface to the next? Is it a horizontal gap, like a space between surfaces, or a difference in height? Try a spot render up close (real close), tangential to the surface to see any difference in height and/or any gaps between surfaces at the seams. Bump maps don't physically displace the mesh, but they do mimic surface details so the shader might be picking up something. The resolution is different for different surfaces, so maybe they need different bump settings. The bitmaps might all be 4K, but the face, for example, is a lot smaller than the torso, so it gets more detail per square inch of bitmap.

Try the process on another figure or texture set to see if it gives the same results. (Hint: you can save only the wet look parameters as a material preset, just deslect all other settings when saving, then you can quickly apply it to any figure instead of dialing it in every time).

If anyone else has any ideas, feel free to jump in. AFK for a while...

Thanks for this detailed guidance. I was getting lost in all the variables, and decided that the wet look method I was using was to time- and labor-intensive. I'm using another one now that utilizes a glossy channel map, and seems to have alleviated the issue. I can still use a lot of your tips in general practice, however. Thank you.