Fly-Navigation

ASDW or Arrow Keys: Move through scene
Left Mouse: Rotate camera

Orbit-Navigation

Left Mouse: Rotate camera around pivot.

Right Mouse: Pan camera & pivot.

Zoom to Point Cloud

Moves camera so that the whole point cloud is within the view area.

Distance Measurement

Left Mouse: Insert Measurement Point
Right Mouse: Finish insertion
Drag & Drop: Move Measurement Points
Distance between measurement points will be displayed on the edge.

Area Measurement

Left Mouse: Insert Measurement Point
Right Mouse: Finish insertion
Drag & Drop: Move Measurement Points
Distance between measurement points will be displayed on the edge and the total area on the centroid. The area is calculated on the ground plane. The height does not affect the result. Crossings should be avoided.

Volume Measurement

Left Mouse: Insert Volume or Select Inserted Volume
E, R, T: Switch between translation, scale and rotation mode.
Volume will be displayed on the objects centroid.

Height Profile

Left Mouse: Insert Profile Marker
Right Mouse: Finish insertion
Drag & Drop: Move Profile Marker
ctrl + Drag & Drop: Drag upwards to increase or downwards to decrease the profile width
Depending on the Clip Mode, points inside the profile will be highlighted or points outside the profile will be clipped.

Source: https://github.com/potree/potree