title: Making a glow node in SceneKit
body: <p>I have a node (just a simple node with an SCNCapsule geometry, just to be more specific) and I want it to glow just like a Star Wars lightsaber:</p>
  
  <p><img src="https://i.stack.imgur.com/TRYVX.png" alt="image"></p>
  
  <p>I have tried to add a child node with same geometry, just a little bigger, opacity of 0.5 and different colour, but it's not exactly what I want. Is there another way to do it? </p>