Normal Map, Bump 2D, Bump 3D and their color spaces

[ulrichGTAV3]

Hi all! It is a bit embarrasing to ask this after working with arnold for almost 3 years:

What exactly is the difference between the nodes "NormalMap", "Bump3D" and "Bump2D"?

As I would understand it "Normal Map" uses a classic "3-channel-normal-map". But those also work with "Bump2D".

Height maps only work with "Bump2D". So often I just use "Bump2D" even for the (blueish) nromal map files.

"Bump3D" does not do anything for me with either a height map file or a normal map file. 

And about color space. I usually have my projects (c4d) and my arnold output on OpenColorIO//ACES. And leave all files color space on "auto". Recently someone said, I should set all image nodes to "raw". But most of my texture files (even normal maps) are 8bit sRGB. So "raw" feels wron to me. 

Anyways. Thanks for any insight!

Laters...

 

[ulrichGTAV3]

I lied (or was just stupid): Most of the times my normal map files are set to "raw". Which is even more confusing, because xnView says they are 6bit sRGB.

[peter_horvath · Accepted solution]

bump2d and bump3d expects a height map (grayscale), while normal_map expects a normal map (RGB image, each pixel representing a normal vector at the given point). The difference between bump2d and bump3d is how they calculate normals from the height map, bump2d is in UV space, bump3d is in object space.

The color space really depends on how the data is stored in the map. Ideally, height maps and normal maps store the raw data, with no color transform, despite the image format. At least that's what the plugin expects, thus sets the color space to 'raw' by default. But again, it depends on the software and settings writing the textures.

[ulrichGTAV3]

Ok, will have to go back and check some of my projects. Have been using that wrong the whole time...