Negates this quaternion in place.
SIQuaternion.NegateInPlace();
dim q1 ' Create Quaternion. set q1 = XSIMath.CreateQuaternion(1.0, 1.0, 2.0, 3.0) 'q1 = -q1 q1.NegateInPlace
SIQuaternion.Negate SIVector3 SIMatrix3 SIMatrix4 SIRotation SITransformation SIQuaternion
