GroundElevationVolumeVisualizer

The zero clock angle follows the x-axis of Entity#orientation, projected onto the local horizontal plane, when it is defined. Otherwise it points in the direction of the entity's horizontal velocity relative to the inertial frame, matching the x-axis of a central body inertial (CBI) vehicle velocity, local horizontal (VVLH) frame. Because the Earth rotates, a stationary entity's zero clock angle points east. When the velocity cannot be computed, it points north.

CBI suits satellites, but for slow vehicles near the Earth, such as aircraft and ships, the Earth's rotation dominates the inertial velocity, so the zero clock angle can be far from the direction of travel. For these vehicles, set the orientation to a VelocityOrientationProperty, which follows the Earth-relative velocity, matching a central body fixed (CBF) VVLH frame. This only affects volumes limited by clock angles; a full cone is the same in either frame.