This script was requested in one bulgarian forum.
The main purpos of it is to find the longest edge of the selected UV island and rotate that island around this edge on predefined angle.
You can align selected UVs horizontally or vertically around the selected edge(this can be the longest edge or the any other edge).
There are two mode of working - "auto" and "manual". In "auto" mode the script will find the longest edge of each UVs and will use that edge as point of rotation/aligning. If there are two or more edges with same length only one of them will be used. In "manual"mode the rotation/aligning will be around the selected edge.
Credits to Hendrik-Jan Schoenmaker a.k.a. renderhjs
Installation: Drag and drop Rotate_UVs_v10.ms in 3ds max. Go to Customize - Customize User Interface - "miauu" category.