Using Auxiliary Coordinate Systems

You can define new x- and y- axes in your design plane and save them as an auxiliary coordinate system. You can save several auxiliary coordinate systems and quickly choose any of them to use, as well as the DGN file or view coordinate systems.

If you have an auxiliary coordinate system stored in another DGN file, you can import it into your current file.

The drawing plane coordinate system used with AccuDraw serves much the same function as an auxiliary coordinate system but is even more useful.

Auxiliary coordinate systems can be particularly helpful in 3D design, where they facilitate placing elements on planes at different depths and orientations. See 3D auxiliary coordinate systems.

Once an auxiliary coordinate system is active you can use it with precision input key-ins (such as AX= and AD=) to perform precision input with respect to the auxiliary coordinate systems. See Precision input key-ins with an ACS.

To define and save an auxiliary coordinate system in a 2D design by data points

1. (Optional) From the Settings menu, choose View Attributes (or press <CTRL-B>)
   or
   (Optional) From any view window's control menu, choose View Attributes.
   The View Attributes dialog box opens.


2. (Optional) In the View Attributes dialog box, turn on ACS Triad and click All.
   When an auxiliary coordinate system is defined, two arrows indicating the positive x- and y- axes and their origin display. (This symbol is called a “triad” because it consists of three arrows in 3D designs.)


3. From the Utilities menu, choose Auxiliary Coordinates.
   The Auxiliary Coordinate Systems dialog box opens.


4. From the dialog box's Tools menu's Define By Points submenu, choose Rectangular.
   The prompt in the status bar is “Enter first point @ x axis origin.”


5. Enter a data point to define the origin of the auxiliary coordinate system.
   The coordinates of the point identified will be 0,0 in the auxiliary coordinate system. The prompt in the status bar is “Enter second point on x-axis.”


6. Enter a data point to define a point on the positive x-axis.
   The ACS triad displays.


7. In the Auxiliary Coordinate Systems dialog box's Name field, key in a name of up to seven characters to identify the auxiliary coordinate system.


8. (Optional) In the Description field, key in a description of up to 28 characters to help identify the auxiliary coordinate system.


9. Click Save.
   The new auxiliary coordinate system displays in the list box.