public ParticleSystem(float deltaT, boolean randomStart) {
		this.deltaT = deltaT;
		if (!randomStart) {
			for (int i = 3; i < 8; i++) {
				for (int j = 15; j < 250; j++) {
					for (int k = 3; k < 6; k++) {
						particles.add(new Particle(new Vector3(i, j, k), 1f));
					}
				}
			}
		} else {
			for (int i = 0; i < 5000; i++) {
				particles.add(new Particle(new Vector3((float) Math.random() * rangex, (float) Math.random() * rangey, (float) Math.random() * rangez), 1));
			}
		}
		// create cell grid
		grid = new CellGrid((int)rangex, (int)rangey, (int)rangez); // should be whatever the size of the box is
	}