This dialog box specifies the settings for the rulers and grid lines. You can have separate settings for the horizontal and vertical rulers and grid lines.
Rulers
Subdivisions
Specifies how many tick marks are on the vertical and horizontal rulers. You can choose Fine, Normal, or Coarse.
Ruler zero
Specifies the location of zero on the horizontal and vertical ruler. By default, the horizontal ruler's zero point is the left edge of the page, and the vertical ruler's zero point is the bottom edge of the page. For example, if you specify 3 inches for both rulers, the ruler zero is positioned to the right (for the horizontal ruler) and 3 inches toward the top (for the vertical ruler).
Grid
Grid spacing
Specifies how far apart the grid lines are. You can choose Fine, Normal, Coarse, or Fixed.
Fine, Normal, and Coarse set the grid to a variable grid; the grid spacing changes as you zoom in and out. Fixed sets the grid to a fixed grid; when you zoom in or out, the spacing between grid lines does not change.
Minimum spacing
For Fine, Normal, or Coarse grid spacing settings, specifies the minimum space between grid lines.
For Fixed, specifies how far apart the grid lines are. Use this option for lines that represent the same distance regardless of zoom level. A fixed grid is especially useful in floor plans and maps where you always want grid lines to show the same measurement (such as an inch, centimeter, or a foot.
Enter the minimum spacing required between lines for each axis, and the grid will retain a fixed perspective throughout your design process, regardless of zoom level.
Grid origin
Specifies where to place the grid origin. By default, the grid origin is in the lower-left corner. You could use this option to move the grid in increments different from the ruler to align the grid with a shape or part of the drawing.
