A new one click system has been added to easily load in all the textures exported from Mari and create a new material for each UDIM found. What would normally take hours to do manually (and sometimes can't be done at all using C4D alone) can now be done in seconds.
Load in your 3D file.
Make sure the object you imported is selected in the Object Manager in C4D
Open up the Material View from the Plugins 4D menu.
From the UDIM Material menu choose Setup UDIMs for Object.
Select a texture in the folder that contains all your named UDIM textures that were exported from Mari.
Press Setup Selected to do the following
Create a new material for each UDIM
Create a selection tag for the UVs for each UDIM and assign it to the material
Load in all the textures from the folder and assign them to the correct channel on the UDIM.