Hi psussi,
In the Material, go to the Assign Tab. Select all Selection tag icons, and right mouse click> Select Tag. This gives you new options> Attribute Manager.
There are many variables in this question, and I have no idea what selections you made while importing it:
https://help.maxon.net/r23/en-us/Default.htm#html/58141.html?Highlight=cad
This is about five different CAD formats.
For all five of these the following applies:
None: no materials will be imported.
Original: if the CAD file contains materials, these will be converted to Cinema 4D materials (primarily, the diffuse color and specular will be assumed) and assigned to the respective objects.
Based on Display Colors: if display colors (not materials) are assigned in the CAD file, these will be imported as materials and assigned, if necessary with the help of polygon selections. The colors’ RGB values will be assigned as material names.
Original with Random Color: If the CAD file contains materials, Cinema 4D materials with a random color will be created and assigned to the respective objects.
If the cad format came from Nemetschek’s own apps, then this might be more helpful
https://help.maxon.net/r23/en-us/Default.htm#html/44461.html#PLUGIN_CMD_1026593
I do not have a general answer to your question, nor do I know what you are dealing with (Import settings, format, etc.). No promises, but I can take a look at the file. Check your Private messages for an upload link.
Cheers