title: 3D: Keeping a point in front of the camera
body: <p>I'm having a bit of a noob math problem here.
  Given the 3D position coordinates and orientation vector of an object (say, the camera), how would I calculate the position in space of a point that would be, say, 2 units in front of the camera?</p>
  
  <p>A metaphor for this: the camera is your head, and the tip of your nose is that point whose coordinates I'm trying to calculate. Its position and orientation are always relative to that of your head.</p>
  
  <p>Thank you!</p>