To Marker | (Required) The coordinate system marker whose angular velocity is being measured. |
From Marker | (Optional) The coordinate system marker whose angular velocity is subtracted off. If you don't specify this argument, it defaults to the global coordinate system. |
About Marker | (Optional) The coordinate system marker about whose x-axis the angular velocity is measured. If you don't specify this argument, it defaults to the global x-axis. |

is the angular velocity vector of the To Marker, T, with respect to the ground reference frame, G.
is the angular velocity vector of the From Marker, F, with respect to the ground reference frame, G.
is the unit vector along the x-axis of the About Marker, A.