Also, because both applications use .5 point (a Point is 1/72 of an Inch) as the basic unit for measuring line and paragraph spacing, it is not possible to set some fixed line spacing intervals. If you enter an invalid spacing measurement into the Paragraph format dialog, you may notice that ClarisImpact will automatically round it to the nearest valid interval after you click OK to confirm the setting.
For example, if you try to set your text to have a line spacing of .2 inch, ClarisImpact will round that to .19 inch, which is the equivalent of 13.5 points. You will only see .19 inch after you click OK and exit the dialog. (Clicking Apply does not force ClarisImpact to change the value to a valid entry, though it does allow you to see the results of the change to your document.) You can always use whole numbers for fixed line spacing, so you can enter 1 centimeter or 1 pica, even though it does not round evenly to a half point.
In addition, if you use "lines" as the measurement when setting the distance between paragraphs (either of the settings for "Space Before" or "Space After"), you are limited to whole line increments. For example, you could not set 1.5 lines before or 2.75 lines after, though you could choose 2 lines before the paragraph and 3 lines after the paragraph. To assign paragraph offset in smaller increments, you must use one of the fixed line spacing measurements. Keep in mind the paragraph above which talks about the accuracy of those fixed measurements.
You can use the following table to find a valid measurement for paragraph or line spacing:
.5 point = 1/144 inch = 0.0069 inch = 0.0017 pica = .1764 mm = 0.01764 cm
1 in = 6 pica = 25.4 mm = 2.54 cm = 72 pt
1 centimeter = 0.3937 in = 0.43 pica = 10 mm = 28.35 pt
1 millimeter = 0.0394 in = 0.04 pica = 0.1 cm = 2.84 point
1 pica = 0.1667 in = 0.0066 mm = 0.066 cm.