hi @simon9,
i coded up a small plug-in for that as i also often thougth this would be nice to have:
I’ll upload the current version here right now and add some more options later on.
Rhino 6 Windows
ScaleOverlay.rhp (44.5 KB)
Rhino 6 Mac
ScaleOverlay.macrhi (17.7 KB)
The Plugin Adds just one Command: ToggleScaleOverlay which enables (or disables) the overlay.
Let me know what you think i plan on adding a simple options page for color, textheight, margins, etc…