_{A cylinder with its side in u0,v0, base in u0,v1, and top in u0,v2}

UDIM values are a way of representing the integer coordinates of a texture, from the coordinates of its bottom-left corner in UV space. This way, multiple textures can be used to cover a model, rather than a single, much larger texture.

_{Faces of a cube unwrapped in u0,v0, to u0,v5,}

It is a 4-digit number starting at 1001, created using the formula, 1001 + u + (10 * v)

In the example above the side would be 1001, base 1002, and top 1003.

To use this method in your file inputs, use the tag in the file name, which is then replaced with the appropriate number.

texture.<udim>.exr will be read as texture.1001.exr when looked up for rendering.

texture_<udim>.tx will be read as texture_1001.tx when looked up for rendering.