public boolean equals(Object obj)
	{
		if(this == obj)
			return true;
		if(!(obj instanceof Vector3D))
			return false;
		Vector3D v = (Vector3D) obj;
		return (v.x >= x - Util.EPSILON && v.x <= x + Util.EPSILON
				&& v.y >= y - Util.EPSILON && v.y <= y + Util.EPSILON
				&& v.z >= z - Util.EPSILON && v.z <= z + Util.EPSILON);
	}