When drafting in the Autocad 2d interface it can be useful to set up a grid to align and distribute the various elements of the drawing. For example, if you were drawing a floor plan it could be useful to see a grid in order to evenly place structural support beams. Alternatively, in the example of a circuit board diagram, you may wish to draw equally spaced tracks and connectors. As we draw, the cross hairs of the cursor will jump to points as defined by a rectangular grid. The cursor movement in this way is restricted to intervals specified by the user, for example 5 metres or 10mm in both the X and Y directions. Another possibility is an aspect ratio of non-equal spacing along both axes, for example, 100mm along the X axis and 150 along the Y axis.
It's also possible to create an isometric or a polar format for your grid. When the Snap function is turned on, the keyboard shortcut for which is F9, the geometry drawn will be locked into an alignment with the specified snap points. This array of snap points is invisible until the Grid command is activated. The keyboard shortcut for this is F7 on a PC and Control+G on the Macintosh. Older versions of the program show the grid displayed as a series of white dots on the black Model Space screen, but the Autocad 2013 release changed this to a grid of light grey lines. The grid itself functions in the same manner though.
The settings for both Snap and Grid may be accessed by right-clicking on either button on your bottom Status bar, or by typing grid into the Command line at the bottom of the interface. This grid is usually used only as a visual reference; we usually do not wish to print it. It can also be displayed in the Paper Layouts, but this is fairly uncommon.
Note also that the Grid array may equal the Snap array or a different spacing and aspect ratio can be specified to that of the Snap. For beginners it's probably best to have the grid and snap settings equal, until you are proficient with the function. By default the X and Y grid and snap spacings are equal but these can be altered by unticking the check box. A value of zero will set the grid and snap spacing to be equal. If, after making the grid visible, you find that the full grid is not displayed, simply zoom in, double-click the mouse-wheel and pan across the screen to make it visible. This happens when Adaptive Grid is checked. This means that when you are zoomed out, Autocad will only display every tenth grid point. Otherwise, in a large drawing, when you zoom out, the screen will be dense with grid lines. We usually also tick Display Grid Beyond Limits this will show the grid beyond the limits of the page.
The Snap and Grid functions are not essential to use, and beginners may choose to turn them off when first learning the program. For very small drawings of machine parts, etc, it can be helpful to draw according to a millimeter grid, and for very large civil drawings a grid of one meter may be helpful. The grid can still be overridden by entering measurements manually however.
Tom Gillan has been training AutoCAD 2D to corporate clients in Sydney for seven years. Visit Design Workshop Sydney for more information.