It is possible to create arbitrary user data that can be attached to any object. This user data can then later be used at shading time by specific nodes with a user prefix.
Information about User Data shaders can be found here.
The convention used to store the user data can be found in different data types such as color, float, etc. For example:
- Create a float user data in C4D and call it 'TestFloat':
- Export the scene as an .ass file and open it in a text editor. We can see that the float 'TestFloat' is stored in the .ass file as follows:
If display color of an object is enabled we will export the 'display_color' RGB as a user data.