Original Post
I have seen this fromula for rotating a vector by a quaternion: v' = Im(q*v*(-q)) where (-Q) is the conjugate Wich many articles describe as 'The Transformation Law'. I've tried it using the rules described in several books and pdfs for multiplication by the two entities. However, when I create a quaternion like this: ... Quaternion Q(cos(theta), sin(theta)*axis); ... and then 'rotate' by using the above formula, the result is most certainly not a rotation, let alone anything meaningful. I have thouroughly checked my operators to ensure that they were identical to those described in each article. However, in every article and book, there has always been a missing gap of information regarding how to properly create a quaternion for said rotation. I have consulted many articles on this; some say that you accept a vector as a quaternion with 0 real part, others say that you create one through the quaternion exp() function, and the rest say that you create one just as I did above. None of these worked for me. Am I missing a step somewhere? Any help will be greatly appreciated!
