Symmetrize UV Util is an add-on that lets you symmetrize your UV map along a specified axis. It is useful to keep the UV map symmetrical when your mesh is modified (added/removed vertices).

🪄 Symmetrize

If your UV map should be fully symmetrical, just use the Symmetrize function. This function makes the UV map symmetry along the specified axis on the panel. 

🪄 Symmetrize by Brush

If your mesh has some asymmetrical parts, you can try the 'Symmetrize by Brush' feature. When you trace some parts with the special brush, the only traced parts are symmetrized. The size of brush can be changed by pressing the 'F' key.

🪄 Expand UV

"Expand UV" (formerly "Mirrored Copy") is a feature that creates a double-sided UV map from a single-sided UV.

🪄 Open Wings

"Open Wings" feature is similar to the "Mirrored Copy" feature, except that it also scales down the expanded UV map to fit the UV boundary.

This feature is intended for the following situation:

1. Create a model with a mirror modifier.
2. Unwrap the model. (Single-sided UV map is generated)
3. Apply the mirror modifier.
4. Use the 'Open Wings' feature. (Now you get a double-sided UV map)

Changes

Ver. 1.3.2 (Jan. 9, 2023)

• Minor UI adjustment.
  
• Refactoring source code.

Ver. 1.3.1 (Oct. 11)

• Some indicators are now displayed correctly for UDIM.

Ver. 1.3.0 (Oct. 10)

• The position of the mirror axis can now be changed (center/start/end/2D cursor).
• Symmetrization can now use selected vertices optionally.
• Source code reorganized.

Ver. 1.2.1 (Aug. 7)

• Fixed bug: The brush does not work when LMB is pressed without moving the mouse.

Ver. 1.2.0 (Jul. 30)

• Added Mirrored Copy feature.

Ver. 1.1.0 (Jul. 21)

• Added Open Wings feature.
• Fixed bug: The add-on is crashed when a mesh that has mirror modifiers is symmetrized.

Ver. 1.0 (Jul. 3)

• Initial release.