2013

Table Of Contents
direction. This icon warns you not to use your pointing device to specify
coordinates.
When you use the pointing device to locate a point, it's normally placed on
the XY plane. If the UCS is rotated so that the Z axis lies in a plane parallel to
the viewing planethat is, if the XY plane is edge-on to the viewerit may
be difficult to visualize where the point will be located. In this case, the point
will be located on a plane parallel to your viewing plane that also contains
the UCS origin point. For example, if the viewing direction is along the X axis,
coordinates specified with a pointing device will be located on the YZ plane,
which contains the UCS origin point.
Use the 3D UCS icon to help you visualize which plane these coordinates will
be projected on; the 3D UCS icon does not use a broken pencil icon.
Enter Coordinates to Specify Points
When a command prompts you for a point, you can use the pointing device
to specify a point, or you can enter a coordinate value at the command prompt.
Overview of Coordinate Entry
You can enter two-dimensional coordinates as either Cartesian (X,Y) or polar
coordinates. When dynamic input is on, you can enter coordinate values in
tooltips near the cursor.
Cartesian and Polar Coordinates
A Cartesian coordinate system has three axes, X, Y, and Z. When you enter
coordinate values, you indicate a point's distance (in units) and its direction
(+ or -) along the X, Y, and Z axes relative to the coordinate system origin
(0,0,0).
In 2D, you specify points on the XY plane, also called the work plane. The
work plane is similar to a flat sheet of grid paper. The X value of a Cartesian
coordinate specifies horizontal distance, and the Y value specifies vertical
distance. The origin point (0,0) indicates where the two axes intersect.
Polar coordinates use a distance and an angle to locate a point. With both
Cartesian and polar coordinates, you can enter absolute coordinates based on
the origin (0,0), or relative coordinates based on the last point specified.
156 | Chapter 6 Create and Modify Objects