This video explains the updates to the UAC Rig in the 2.8 version put out on August 3rd 2021. The main focus is the new terrain connection and the ability to rig doors, bonnet and boot.
[ v2.8 ] - 8/3/2021 1) Terrain connection button added to the UI. This will connect all of the wheels on your vehicle to to your selected terrain using a combination of the maya muscle system and geometry constraints. Geometry constraints alone were not accurate enough and had consistent slipping. 2) Terrain influence and offset attributes are located on the drive control. Individual influence attributes are located on each wheel. 3) UI has been reorganized. 4) UI now has icons instead of text buttons for the connection area. 5) You can now connect front doors, rear doors, bonnet and boot. 6) LT button was previously used to load a rig without tire deformation, this button is now replaced by the Tire Deformation Division button. Setting it to 0 will load a Lite Rig with no tire deformation. 7) You can now connect non-mesh objects such as vray nodes or headlights to the rig using the same connection buttons. 8) Control size attributes are added to each control. This is useful when your vehicle is covering your controls. 9) Unused Influence optimization is now done at the code level which means the Annoying optimize prompt is now gone! However, you will receive a redundant influence warning in the script editor print out that will look something like this: "Warning: The two surfaces have different numbers of influences (8 and 2). Weight transfer may be problematic near the missing influences." 10) Referenced mesh connection improvements and warning messages in place. 11) Connection speed increased on all methods. 12) Adding closed curves(loops,circles etc.) as paths would open them, leaving a gap once connected. This is now fixed. 13) Selecting any control of a vehicle will now work when setting an active vehicle.