These UnDPs poll values from the Cisco-CAT6K-CROSSBAR-MIB. They will return inbound and outbound percent utilization for the switch fabric. Depending on which modules you have in your 6500 and the switching mode you have configured, your modules may use the system backplane or the switch fabric or both. On the node details page of our 6500s, I have a table listing the module inventory (from mtxpert's UnDP: Cat 6500/4000 Inventory (Includes Slot, serial, model and firmware version)), the Backplane Utilization table and the Fabric Utilization table (The UnDP for the Backplane Utilization is here: Cisco 6500 Backplane Utilization)
The values returned here should be roughly the same values you'd get from running the "show fabric utilization" command. Just keep in mind that the UnDP values are tied to your Statistics Collection cycle, so they will only update as often as you have your Statistics Collection task set to run in Orion. I set the UnDP to keep historical data, so we could have a history of the fabric's utilization.