In this tutorial we’ll see how to set up a UDIM texture in Blender tutorial by Richard “Dikko”. 
In this video we tackle a fairly advanced feature in Blender – UDIM tiles!

How to use UDIM in Blender?

This video will guide you through how to set up a UDIM texture, and what you need to consider about them when you need to export your model to other software such as Substance Painter for texturing.

What is UDIM?

Using UV maps can have one disadvantage, they consist of one texture for the entire mesh. Most of the time this is sufficient but the disadvantage is that the texture is one resolution for the entire mesh.
This causes issues if you have a very large mesh with geometry of different importance. When using a singular texture, the resolution might be too low to cover larger UV islands while being inefficient for smaller, less important islands.

UDIM offers a solution to this by being able to spread UV islands across several different textures. UDIM which stands for U DIMension is based on a tile system where each tile is a different texture in the overall UDIM texture array.

Basically each tile consists of its own UV space (0-1, 1-2, 2-3) and have its own image assigned to that tile. Tiles are managed in the UDIM Tiles panel where they can have a generated image assigned to them.

Generally, you create several textures of different resolutions; for example, you may have a 4k resolution texture for the major details, and 2k and/or 1k textures for less important details.

For more info: docs.blender.org/udims