Runs with the length tool. Click along a run, through as many corners as it has. Shift keeps each new point on a 45-degree step from the last one, Backspace removes the last point, Enter or a right-click finishes, and Esc cancels. The total length appears in the Marks list as soon as the run is finished.
Single distances with the segment tool. Two clicks give one straight distance. It is the tool for checking a scale against a second printed dimension, and for short items such as a door opening or a countertop run.
Areas, rectangles, and rooms. The area tool takes the corners of a boundary one by one; click the first point again or press Enter to close it, or drag to draw a rectangle. The room tool adds a room's area from one click inside it. Where walls are drawn filled on a calibrated sheet it measures wall to wall, and Shift+click measures only the open floor. It needs a closed room: an open-plan space, a dimension line across the room, or an opening without a door symbol means drawing that area point by point. Each area also shows its perimeter.
Counts in groups. The count tool adds one item per click. Esc closes the group, and the next click starts a new one, so outlets, sprinkler heads, or light fixtures can each keep their own label and total.
Snapping and editing. New points snap to corners of other marks on the sheet, which keeps adjoining runs and areas joined. They do not snap to the drawing's own lines, so zoom in where it matters. With the Select tool, drag any corner or a whole mark, and undo reaches every change.
Units that suit the job. Lengths can show as feet and inches, decimal feet, inches, meters, centimeters, or millimeters; areas as square feet, square meters, or square yards; volumes as cubic yards, cubic feet, or cubic meters. Changing a unit changes how the totals read and export, not the marks themselves.
What every number rests on. Each sheet has one scale, so a detail drawn at a different scale on the same sheet will not read right. There is no circle or arc tool; trace a curve with several points. Above all, a measurement is only as good as the calibration and the drawing, which is why the second dimension check comes before the takeoff, not after it.