In three-dimensional space, the right-handed rule is usually used to determine the direction of the coordinate axis. The x-axis usually represents the horizontal direction, the positive direction usually points to the right, and the negative direction is the opposite. The Y axis represents the vertical direction, with the positive direction usually pointing upward and the negative direction pointing downward. Z axis represents the depth direction, the positive direction usually points to the back of the observer and the negative direction points to the front of the observer. This law is often used in the coordinate system of mathematics, physics, computer graphics and other fields.