title: How I can I delete sprites without obstructing the physics in SpriteKit?
body: <p>I want to make a game in which sprites fall from the sky and stack up on the floor, however when there is a lot of layers the camera will move up so you can continue playing. After a while more and more rows of sprites will become invisible as the camera moves up. I want to delete these unused sprite-nodes to keep the performance as good as possible. But when I delete the nodes at the bottom of the stack, won't the entire thing collapse? Or should I detect when the bottom row is unused and then turn off physics for the row above it so it wont fall down and won't affect the rows above it or something of that nature.</p>
  
  <p>I haven't actually made any code yet, I just wanna have a good idea of what I'm doing before I start the wrong way.</p>