Sometimes, you need to add or subtract a smidge from your measurement. Examples include window and door trim with a reveal and taking off a blade width to ensure fit. To add an offset, just drag the tape view on the top of the cut list, as shown in the illustration below. To subtract an offset, drag the other direction. The red line on the tape always indicates your current cut length. The blue line indicates your original cut length (sans offset). In the illustration, a 3/16" offset is being added to a measurement of 137 5/8". The default offset is 1/4", but you can set whatever value you need using the Set Offset Value dialog, accessible through the Offset button on the left side of the tape view.
If you're using multiple materials on a job or if you want to use the Advanced Miter functions, you need to specify the material you're using. Not only can you set material from the default list, but also specify your own custom materials.
When specifying a new material or changing an existing one, the description can be set to whatever you'd like. You may set any decimal values for width, length, and depth. The width is the value used to calculate additional length from miters. When you select the Show In List checkbox, that material is shown in the cut list you're coming from. For example, if you're in Crosscuts, your material will be available in all Crosscuts lists. If you want to remove a material altogether from all lists, swipe it from the material list.
In some instances, when you add a miter cut, you're measuring the short side. Examples of this include window and door casing and outside corners for baseboard or crown molding. If you have the correct material width set, Measure will calculate the long side of the board for you when you check the Add Miter Selection to Cut Length checkbox in the Miter dialog.
Other times, you're already measuring to the long side. Examples include inside corners for crown and baseboard molding. In these cases, be sure not to check the Add Miter Selection to Cut Length checkbox. Otherwise, you'll end up with too long a cut.