This is the introduction to the RemapPSD Maxscript by David Shelton which can be downloaded at davidshelton.de/blog .

RemapPSD bridges the power of render to texture inside 3ds Max and the photoshop application. With this script you can easily map your entire photoshop file to a different set of uvs. The script will handle complex photoshop files, layered tiffs or any other image file that can be written and read by 3ds Max and Photoshop. The photoshop file can include:

- layers with masks
- folders with masks
- folders inside folders
- adjustment layers with masks
- and more...

Basically you need three things to make the script work.

1. Any piece of textured geometry
2. Two sets of UV's: Channel 1 for the old mapping, Channel 2 for the new mapping
3. A standard material with a bitmap texture as it's diffuse map

RemapPSD will do the rest for you.