GravityVectorInterface

This interface is used to specify the gravity vector. There are two options:

• Provide the direction via gravity_direction. The magnitude may optionally be specified using gravity_magnitude; else it defaults to the exact NIST constant for the acceleration due to gravity, 9.80665 m/s.

• Provide the gravity vector via gravity_vector.

An error will result for any of the following cases:

• Both gravity_vector and gravity_direction are specified.

• Both gravity_vector and gravity_magnitude are specified.

• Neither gravity_direction nor gravity_vector are specified.