Arnold specific parameters can be attached to each primitive or polygon geometries via the C4DtoA Tags -> Arnold Parameters tag.
C4DtoA Tags menu visible by right clicking in the viewport or Object Manager window
You can edit these parameters via the Attribute Manager by selecting the tag.
The following list of common settings are found within the Arnold tag for geometry (polygon objects):
- Main Settings
- Subdivision Settings
- Displacement Attributes
- Export Parameters
- Motion Vector Parameters
- Mesh Volume
Information about displacement settings can be found here.
Display Color
You can access the Display Color of an object in a shading network via the user_data_rgb shader. Just use the display_color as the Attribute Name.