Difference and how to use DISP/DISP16 / BUMP / NORM / GLOSS / REFL maps

Question

So I know the basics ob pbr textures but everytime I download a pbr texture and unpack it I am suprised by some new names or different wording.

This time I downloaded a leather texture that has 11 image textures in it.

1. Question. Whats the difference between Refl and Gloss. I would have guessend Gloss is specular and then Refl is the roughness? Should I just try and judge of looks if I am right? Problem is I have very little experience and no clue how "good" materials should and can look.

2. What the difference between DISP / BUMP / NORM ? I would just use Normal in combination with a Normal Map and put it into normal of my Princibled BSDF.

3. WHats the fidd between BUMP and BUMP16

3x Color variants 1x AO okay 1x BUMP 1x BUMP16 1x DISP 1x DISP16 1x NRM 1x GLOSS 1x REFL

Answer 1

• Gloss is inverted roughness.
• Reflection is for Specular although this isn't technically realistic so is only used in non-PBR workflows.
• Displacement is a B/W image used to displace geometry. Used with a Displacement node plugged into Displacement in the Material Output.
• Bump is a B/W image, similar to displacement as it is height information, but is intended to affect light bounces only and not displace geometry. Used with a Bump Node plugged into Normal in the shader.
• Normal is similar to Bump in the way that it only affects how the light bounces. This contains vector information instead of height information. Used with a Normal Map node plugged into Normal in the shader. Can be chained with a Bump node to combine.
• 16 after an image name represents it being 16bit, so a NRM16 would be an RGB image with a value between 0-65535 for each channel. A standard 8bit images only has 255. For colour, this is usually enough bit depth information. But with normals, using 8bit can sometimes show as jagged edges/sharp angles in the reflection.

Answer 2

What are the different texture maps for? from Poliigon is a good introduction to the kinds of maps and how they are used. To answer your specific questions:

1. Reflection is specular and Gloss is roughness, (actually its inverse,) the opposite of your guess.
2. The differences:
   • Displacement is meant to actually displace the geometry. Feed it to a diplacement node and feed that to the material output.
   • Bump is meant to 'fake' the appearance of geometry that isn't really there. Feed it to a bump map node and feed that into the shader's normals.
   • Normal is a different way to 'fake' the appearance of geometry that isn't really there. Feed it to a normal map node and feed that to the shader's normals.
3. The difference between FOO and FOO16 is that a FOO map uses 8 bit data, which is often enough, where a FOO16 map uses 16 bits. More accurate but takes up more space.