I have the following problem:
Rotations can be done by using quaternions. My understanding is, that to rotate a vector around a quaternion, the vector has to be transformed to a 4-dimensional vector: v = [x,y,z] to v'= [0,x,y,z] This vector can now be rotated around the quaternion using v'2 = q*v'*q' where q' is the conjugate quaternion and the quaternion product needs to be used.
My problem is, I don't understand how to get a 3D vector from the new, 4-dimensional vector v'2 since v'2 = [w,ai,bj,ck]. Do I just disregard w and use v_new = [a,b,c] as my new vector or do I have to do a specific transformation?