This was an add-0n developed and released as part of the German Goodies and it dated back to the original appearance of Zones. It seems to have disappeared. I went back as far as ArchiCAD 12 and it's gone.
This was a useful tool. I used it to prepare area certificates for tenant leases. It showed the calculations graphically to demonstrate the veracity of the calculations.
Another one to bring back and distribute for the rest of us, along with the Japanese overshadowing tool.
Think Like a Spec Writer
AC4.55 through 27 / USA AC27-6000 USA
Rhino 8 Mac
MacOS 14.6.1