UDIM/UVTILE file identification

UDIM/UVTILE files are recognized as such (e.g. by the Open Texture command) if the file names of image sequences contain the following characters:

• four-digit numbers beginning with the digit 1, e.g. xxx_1001, xxx_1002, the numbers indicate the tiles according to the illustration here. The token in file paths for this is <UDIM>.
• _u##_v## , where "##" are numbers, e.g. _u0_v0_xxx, _u0_v1_xxx, where the numbers indicate the tile coordinates in the UV direction. The token in file paths for this is <uvtile> (lower case).
• there are programs that by definition use _u1_v1 as the first tile at the bottom left, in this case <UVTILE> (capitalized) must be used as the token in file paths.

See also the illustration here for the tile designation and coordinates.