@roy12:
In FBX there are no submeshes, but you could have several meshes in one frame. In order to support submeshes most conveniently the number following the underscore is used as submesh index.
Oh I see, so it's an automatic behavior, never mind then. It's just that it kinda makes it harder to automatically replace meshes in frames, since they're almost always named with underscores in vanilla files (for example, if I have 40 separate meshes it's easier to name them the same in Blender as the target frames in the vanilla file so that I can grab them all, drop them anywhere in SB3UGUI and the program will target the frames with the same name as the input meshes). Creating new ones is good, but sometimes I have files where frames have an SRT different to all zeroes. I'm not sure of how to handle these, creating them automatically from the FBX file leaves them with SRT at all zeroes and I could end up with the new hair parts at the wrong position.
In the end I just used a different animator where parent frames for meshes have their SRTs at all zeroes, renamed the vanilla frames to something like hairXpYY, X being whatever hair I'm working on and YY being the part number, and renamed the materials in Blender to the same names as in SB3UGUI, to ease the import of 40 hair pieces (x2 if you count the undersides).
@HanmenNoAsura
You asked if it was possible to add texture maps to existing shaders. Well, I just tried it and it's possible, and it works. I just added a bump map slot to the eye material, gave it a bump map, and set its bump strength to 1, and it works:
Of course, I had to exaggerate the specularity a bit to see it, but you can see how the surface light is being affected by the bump map, specially on the sclera.
I just had to add these two lines in the material properties:
_BumpScale ("Scale", Float) = 1
[Normal] _BumpMap ("Normal Map", 2D) = "bump" { }
However, to be able to actually set the bump map, you have to change the shader, so I made a new file, modified the shader's name, made that modification, copied it to the asset where the material is, and set this new shader for the material. Then you're able to modify these properties in SB3UGUI.