CC3 keeps track of points you select using x,y coordinates. It can also represent coordinates in other ways. Whilst you can select coordinates using the mouse and left button, you can also type them in at the keyboard whenever CC3 asks for a point.
To help you understand numeric coordinates, CC3 can display the current cursor position on the Status Bar in terms of absolute, relative, or polar coordinates. To change tracking modes, click on the Tracking Indicator on the Status Bar.
Absolute coordinates: These are Cartesian coordinates, counted in CC3 units from (0,0).
To use absolute coordinates: Type a pair of numbers separated by a comma (with no spaces between the characters); for example: 4,5. Use negative numbers to indicate locations to the left and below of 0,0; for example: -4,-5.
Relative coordinates: These coordinates tell CC3 to draw from the reference point (last selected point) to a coordinate location a relative x,y distance away.
To use relative coordinates: Type the "at" sign (@), followed by the x,y distance to the desired point. For example, start a line at coordinates (5,2). Type @3,5 to end the line at (8,7). CC3 draws the second point three units to the right and five units up from the first point.
Use negative numbers to indicate locations to the left and below of 0,0. For example: @-6,3.
Polar coordinates: These coordinates use a bearing angle and distance (rather than a pair of x,y coordinates) to select a location in your drawing.
To use polar coordinates: Enter the "less than" sign (<), an angle, a comma, and a distance. For example, <90,2 tells CC3 to place a point 90° (direction) and two units (distance) from the last selected point.
Here's a real-life example of polar coordinates: When you give driving directions to a friend over the telephone, you might say: "At the gas station, turn north and travel two miles." In CC3, the "gas station" is the reference point (last point you used in drawing or editing), "north" is 90°, and two miles could be the two units in the polar coordinate <90,2.
Relative polar coordinates: These are like polar coordinates except that you use a tilde (~) instead of the "less than" sign (<), and the angle you enter is relative to the angle defined by the last two points you used.
For example, suppose you just drew a line from coordinate (1,1) to coordinate (1,3)-a vertical line two units high, with an angle of 90°. If you are still in the LINE command and type ~90,1 the resulting line has an angle of 180° (horizontal) and is one unit long.
In a real-life example, you might tell your friend to "turn left and go one mile." If he or she had just driven two miles north, turning left (~90) would mean heading west (180°).