B313 Sequence: 2nd Rotation (THETA)

Returns the second angle of rotation (in radians) associated with a Body 313 rotation sequence from one coordinate system marker to another. This second rotation is referred to as the theta, , angle, and is used in association with the psi, , (1st rotation) and phi, , (3rd rotation) angles.
Positive angular displacement is determined by the right-hand rule.

Format

THETA (To Marker, From Marker)

Arguments

 
To Marker
(Required) The coordinate system marker whose rotation is being measured.
From Marker
(Optional) The coordinate system marker with respect to which the rotation is being measured. If not specified, this argument defaults to the global coordinate system.

Example

The following example illustrates the use of the THETA function:
THETA(marker_T, marker_F)
See the illustration for B313 Sequence: 1st Rotation (PSI).