private void setParticleField(String str1, String str2, boolean x) {
		int lb = str1.indexOf("[");
		int rb = str1.indexOf("]");
		double z = parseMathExpression(str1.substring(lb + 1, rb));
		if (Double.isNaN(z))
			return;
		int i = (int) Math.round(z);
		if (i < 0 || i >= model.getNumberOfParticles()) {
			out(ScriptEvent.FAILED, "Particle " + i + " doesn't exisit.");
			return;
		}
		String s = str2.toLowerCase().intern();
		boolean b = true;
		if (s == "visible")
			model.getParticle(i).setVisible(x);
		else if (s == "movable")
			model.getParticle(i).setMovable(x);
		else if (s == "draggable")
			model.getParticle(i).setDraggable(x);
		else {
			out(ScriptEvent.FAILED, "Cannot set property: " + str2);
			b = false;
		}
		if (b) {
			view.repaint();
			notifyChange();
		}
	}