UDIM Mode

UDIM is a multi-tile UV system that allows textures of different scales to be applied to specific UV tiles. This enables high-resolution textures for important parts of a mesh and lower-resolution textures for less critical areas.

You can read more about it in Blender's manual.

Switching to UDIM mode when you want to bake UDIM textures is essential. This switch can be done from the dropdown menu of the bake list's button.

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Multiplier

One change for the bake list is that the items' scale changes from a whole number to a decimal number. This number acts as a multiplier for all the tiles' scales. When the tiles are created for the textures, the tile size is multiplied by the baked item's multiplier.

Using the multiplier, you can bake UDIM textures at different scales without adjusting the size of each tile individually. A multiplier of 2 will double the texture size, while setting it to a value below 1 allows you to downscale the tile sizes.

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UDIM Tiles

The main change is the addition of a new UDIM Tiles panel, along with its list operators and item properties. This list holds the UDIM tiles for all the textures.

By default, the list is empty, like the bake list, and it provides an alert when it’s empty. Adding items to the list removes the alert.

You can add multiple tiles at once by holding the CTRL key while clicking. This will open a popup window where you can set the number of items, their scale, and the starting tile.

These list buttons work the same way as the buttons in the bake list. They behave identically and have the same functionalities. The only difference is in the dropdown menu.

When you open the dropdown menu, the only differences are the source image option at the top and the tile label option at the bottom. The rest are the same as in the bake list, providing the same functionalities.

Source Image

Tiles can be imported from an existing UDIM image texture. By selecting the source image option, you can choose a texture, and all its UDIM tiles, along with their scale and label, will be imported into the UDIM tiles list.

Tile label

Tile labels can be enabled for the items in the tile list. When the labels are enabled, they will be assigned to each tile for the UDIM textures.

Once enabled, the labels can be edited by double-clicking the text and modifying it. Pressing the Enter key will confirm and save the changes.

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UDIM Items

Each item in the UDIM list has two main properties: the tile number and the tile size.

Tile Number

The UDIM number of the tile typically starts from 1001 and increases incrementally, with a maximum tile number of 2000. It can be changed by typing in a specific value, dragging it left or right, or using the incremental buttons.

Tile Size

The tile's image scale functions the same as the scale property in the non-UDIM bake list. It can be set from 1 to 65536 and can be changed by typing in a specific value, dragging it left or right, using the incremental buttons, or using the half and double buttons on its sides.

UDIM tiles with the same tile number are marked as duplicates. Only one item should have a specific tile number.