this.thingsToAdd.clear();
Iterator<Thing> iter = this.things.iterator();
LogData.set("numberZombies", getNumberOfThingsOfType(Zombie.class));
while (iter.hasNext()) {
Thing thing = iter.next();
thing.step();
if (thing instanceof Volumetric){
if (this.thingTools.isOutOfRangeOfCamera((Volumetric)thing)){
thingsToRemove.add(thing);
continue;