Hello again! The second shader posted here is a small shader that will display the current UDIM tile number, very handy sometimes!
Page:
http://www.rensheeren.com/blog/osl-show-udim/
Download links:
http://www.rensheeren.com/osl/showUDIM_tex_v001.osl
http://www.rensheeren.com/osl/rhfunctions.h
Save both in the same folder, both are needed for the shader to work.
Enjoy! 🙂