GRD/SNAP allows you to set the grid spacing and snap
alignment within a viewport for use as a drawing aid.
When creating entities, use these two options 
simultaneously for precise results.

To display, align, and set the increment of grid spacing 
and snap alignment, choose the following options:

GRID DSP (Grid Display) - to display a set of
grid points, with the currently assigned spacing and
alignment.

GRID INC (Grid Increment) - to set the spacing between 
grid points along the x and y axis.

GRD ALN (Grid Alignment) - to shift the position of the
grid points to a new location.

GRD=SNP (Grid=Snap increment) - to set the grid
 to the current snap increment values.

SNAP OPT (Snap Option) - to turn the cursor snapping on 
or off.

SNAP INC (Snap Increment) - to set the snap resolution 
along the construction plane.

SNAP ALN (Snap Alignment) - to line up the snap increment
with an indicated position on the grid.

SNAP=GRD (Snap=Grid increment) - to automatically sets the
snap increment to the grid spacing along the x and y axes,
and aligns the cursor snapping with the display grid.
