AutoCAD LT provides two coordinate systems: a fixed coordinate system called the World Coordinate System (WCS) and a moveable coordinate system called the user coordinate system (UCS). The UCS is useful for entering coordinates, defining drawing planes, and setting views. Changing the UCS does not change your viewpoint. It changes only the orientation and tilt of the coordinate system.
If you are creating 3D objects, you can relocate the UCS to simplify your work. For example, if you have created a 3D box, you can edit each of its six sides easily by aligning the UCS with each side as you edit it.
You relocate a UCS by choosing the location of the origin point and the orientation of the XY plane and the Z axis. You can locate and orient a UCS anywhere in 3D space. Only one UCS is current at any given time, and all coordinate input and display is relative to it. If multiple viewports are active, they share the same UCS.
If you plan to work extensively in 3D, you can save by name UCS locations, each having a different origin and orientation, for various construction requirements. You can relocate, save, and recall as many UCS orientations as you require.
Working with the World and User Coordinate Systems in 3D
Controlling the User Coordinate System (UCS) in 3D
Controlling the UCS Icon in 3D