The PSI function expression calculates the first angle (in radians) of a body-fixed 3-1-3 Euler rotation sequence between markers i and j. Marker j defaults to the global coordinate system if it is not specified. For a schematic of the body-fixed-3-1-3 Euler angles, click here.
PSI(i[,j])
| i | The marker whose rotations are being sought. |
| j | The marker with respect to which the rotations are being measured. |
PSI(222,434)
This function returns the psi angle between Markers 222 and 434 in its second column.