Returns the angle between this vector and the vector vector in the range [0, 2 x Pi]. 

If (refVec.dotProduct(crossProduct(vec)) >= 0.0), then the return value coincides with the return value of the function angleTo(vector). Otherwise the return value is 2 x Pi minus the return value of the function angleTo(vector).

Public Function GetAngleTo(
    vector As Vector3d, 
    referenceVector As Vector3d
) As double

public double GetAngleTo(
    Vector3d vector, 
    Vector3d referenceVector
);