title: Find a new 3D position from a known point of origin, based on distance and angle
body: <p>My maths is very rusty and I've never been great at imagining things past 2 dimensional space.</p>
  
  <p>My question is this. Given a point of origin (p1), how can I calculate a new point (p2) which is a known distance (100 units) based on two angles (Yaw and Pitch). </p>
  
  <p>What I know is the 3D dimensions for a virtual room, the point of origin within that room and the Yaw and Pitch (I've called this horizontal angle and vertical angle). To put it in to English, I would like to fire a line of 100 units within this room from that point of origin based on it's Yaw and Pitch values and get the point at the end of that line.</p>
  
  <p>I would like this point in space because I would like to define my line using p1 and p2. I want to eventually go on to use this line in a line/plane intersection test. The planes are also known within the virtual room. I only mention this because with my lack of mathematical knowledge, someone may suggest I look at some other method. </p>