Velocity

Marker in { } is optional. If the user does not define optional markers, those markers use ground inertia marker. The marker name is defined as follows:

(m1{,m2}{,m3}{,m4}) : (bodyname.markername{,bodyname.markername}{,bodyname.markername}{,bodyname.markername}).

•     m1 becomes action marker.

•     If m2 is defined, m2 becomes base marker.

•     If m3 is defined, m3 becomes reference marker.

•     If m4 is defined, m4 becomes the reference marker which is considering a change of Orientation.

Relative velocity between action and base marker() is computed like below formula.

 : Position vector of marker with respect to ground Inertia.

: Orientation matrix of marker with respect to ground inertia.

 : Velocity vector of marker with respect to ground inertia.

: Angular velocity vector of marker with respect to ground inertia.

Generally, m3 is the same as m4. Then, above formua means velocity vector of action marker relative to base marker in the view of reference marker.