The angle of rotation can be found from the trace of the direction cosine matrix to axis angle of rotation matrix
Noting that the axis of rotation is a unit vector and has a length of 1 means
therefore
rearranging gives
![]() |
(1) |
Inverse cosine is a multivalued function
and there are 2 possible solutions for
. Normally, the convention is to choose the principle value such that
As long as
is not zero, the unit vector is given by
![]() |
(2) |
Above equation should be proved at some time...
As of this snapshot date, this entry was owned by bloftin.