Units

Primary Grid Size

This is the measurement between the thicker grid lines. You can select Inch or Centimeter.

Secondary Divisions

This is the number of smaller cells within the grid. The options are 2, 4, 5, 8, 10, or 12.

Tooltip Units

This is for the coordinates that show up near the cursor when drawing. Whether they use the Primary grid size, Secondary divisions, or Combined. For example on an eighth inch grid should a line that crosses twelve cells show 1.5, 12, or 1' 4" for the length.

Tooltip Fractions

This setting combines with the previous one. It is to show the fractional part of coordinates in Decimal or Fractional. For example 1.5 or 1 1/2. Also affects 45.5° or 45° 30' for degrees.