title: Change of direction of a vector
body: <p>Given two vectors in three dimensions pointing different directions. I would like the first vector be able to change direction a set number of degrees towards the second vector. What is the formula or algorithm to calculate this new vector.</p>
  
  <p>For example a space-ship (this is for a space-ship simulator) is pointing in the direciton of (2,3,3). The ship will now change direction 20 degrees in the direction to the vector of (2,-3,-2). What would the new vector be. It is not rotating along an axis, but rather at a right angle to both vectors.</p>