When you select the "Add Object Parameters" button you must then browse the list to find the zone stamp in your library.
Once you select that you will see a list of all the available parameters you can choose from.
Your "Room Finish" should be there but the parameter may not be called "Room Finish" - although it should be something similar.
Barry.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10