The CreaseAngle command allows you to place an angular dimension between two planes in a Rhino model.
1. If you have not installed the latest Microsoft runtime libraries, then download and install them by clicking on the the link http://en.wiki.mcneel.com/content/upload/files/vcredist_x86.exe
2. UnZip the plug-in file CreaseAngle.rhp to a folder on your computer.
3. From Windows Explorer, double-click on the CreaseAngle.rhp file to install it as a Rhino 4.0 plug-in.