Weird seams caused by bump map

Question

I'm new to Blender and I'm trying to combine the head and body from two models I downloaded, the model I want to use the body for has separate textures, normal maps, roughness maps and specule maps for each body part and as long as only the textures are used there are some seams but they are not very visible. But once I activate the normal, specule and roughness maps the borders between textures become much more prominent. I'm pretty sure it has to do with the bump map because this is what the bump map looks like directly plugged into output. This is the node setup I used for the shaders, they are the same for each body part texture. Not sure if it's fit for purpose, I just imitated it from the original model because that one had a bunch of functions I don't need. This is the content of the Normal mix group node. And this the content of the invert group nodes, both are identical. Once I mute the invert group nodes it looks like this. This was the original node setup I copied my setup from, not sure if I removed anything essential. the original setup enabled adding a wet look to the skin but I don't need that so I removed those nodes. The body part textures look like this. And the normal textures like this. I do not have SubstancePaint so I tried fixing the seams with an image editing software butI can't align them well because the border between arms and torso is in the middle of the torso texture image and not the edge like in the arm texture image. What I am looking for ideally is a way to unwrap the mesh again but have it pull the texture along so it creates a new image with all the textures that I can then edit, or a way to separate the faces that have the seams on them and export the texture on them as a separate image for editing. Or any other way to fix this that I simply don't know about. You can download the blender file here. Any help would be greatly appreciated.

Answer 1

The image T_CH_male_body_n2.tga seems to be broken. You need a backup or download the model again, hopefully with a valid unchanged image.

The image contains a normal map (RGB values) and a bump map in the (A)lpha channel = RBGA.

If I open T_CH_male_arm_n.tga (the normal maps for the arms) in Gimp then it looks like a valid normal map. The Alpha channel is turned off to get a better impression:

^{T_CH_male_arm_n.tga - Normal map for the arms}

The main color variations here are around the saturated blue, that's #8080FF the value for a "flat" normal.

Now have a look at the map for the torso that is T_CH_male_body_n2.tga:
^{T_CH_male_body_n2.tga - Normal map for the torso. It's very pale!}

This image is way too pale for a normal map (transparency is disabled). All these light blue pale areas should be darker. The image should look something like this:

.

I've adjusted here the values to give you an impression. The map is just for illustration. It's still not right because it lacks cyan and deep purple values.

Unfortunately, normal maps need to be calculated and can't be painted. So I hope you have a backup. If not, you can try to adjust the color (RGB curves) and smear the still visible seams in Blender. But the result will be poor.

Note: For some reason there is a T_CH_male_body_n.tga and a T_CH_male_body_n2.tga. The only difference is that the 'n' version has no bump data, the alpha values are all set to 1.