An edit-mode helper object to measure distances. (For example, jump heights.)
Also good for orienting yourself in a scene (for example, to judge how flat/steep a hill is to walk).
Cannot be seen when editing sculpts or paintings.
Memory: Costs 0.0061% of the things limit per gadget.
Gizmo: A rectangular transparent box. Hovering over it shows the dimensions of the closest edges in meters.
# X, Y, Z
The length of each side of the ruler.