scale 2d by entered amount

 From:  scott (SSHWARTS)
7874.1 
Is there a script or a (duh!) way that allows you to enter an distance versus a scale factor? I want shrink a closed curve by say 1mm instead of a scale factor. While I can visually do that on the grid, I'd like to be able to enter a number. Or, am I as missing something as usual.

Scott