Use Orthogonal Locking (Ortho Mode) - Autodesk 057B1-41A111-1001 - AutoCAD LT 2010 User Manual

Change Grid and Snap Spacing
As you work, you can turn Grid and Snap mode on and off, and you can
change the grid and snap spacing. You can turn Snap mode on and off
temporarily by using an override key.
Snap spacing does not have to match grid spacing. For example, you might
set a wide grid spacing to be used as a reference but maintain a closer snap
spacing for accuracy in specifying points.
Change the Grid and Snap Angle and Base
If you need to draw along a specific alignment or angle, you can change the
grid and snap angle by rotating the user coordinate system (UCS). This rotation
realigns the crosshairs on the screen to match the new angle. In the following
example, the UCS is rotated 30 degrees to match the angle of the anchor
bracket.
The grid and snap points are always aligned with the UCS origin. If you need
to shift the grid and grid snap origin, move the UCS.
See also:
Set Isometric Grid and Snap
Override Object Snap Settings

Use Orthogonal Locking (Ortho Mode)

You can restrict cursor movement to horizontal and vertical for convenience
and precision when creating and modifying objects.
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