this.activeChild = child;
if(activeChildData != null) { activeChildData.setIsCollidable(false); } this.activeChild = child;
	public void setActiveChild(int child) {		if (child < 0 || child > getQuantity()) {			activeChild = SN_INVALID_CHILD;		} else {			this.activeChild = child;			activeChildData = getChild(activeChild);		}	}