This is a bracket based off the design by Grabercars. This version allows you to have a rectangular piece as well.
Input the actual horizontal/vertical measurments (length & width) of your heatbed and glass. The SCAD will automatically create the correct notches in the bracket for your glass/ heatbed.
This model assumes your support (I use a layer of cork) is the same horizontal/vertical size as yout heatbed.
The PlatformCoverage variable allows you to adjust hor far the bracket extends over your bed.