A two-point line labelled with the real length it measures.
The Dimension draws a two-point line with an arrowhead at each end and labels it with what the line
actually measures on the sheet. It is the quickest way to answer "how far is that" without starting
a takeoff.
Draw it: press at one end, drag to the other, release. The label appears as you drag.
Settings
Thickness: 1 to 10, half the ceiling of the other linear tools. A dimension is read, not seen.
Font size: default 8. Sets the label.
Font colour: a separate channel from the line colour, so the label can be picked out against a busy sheet.
Start ending / End ending: closed arrowheads by default, settable to any of the nine styles.
Opacity: none.
Notes
The label reads in feet and inches to the nearest fraction, off the page's scale, and is re-read every time. A line drawn before the page was scaled still labels, but the number means nothing until the scale is set. See Setting a scale.
The label sits above the middle of the line and rotates with it, and is never drawn upside down: a line running right to left carries its label the same way up as one running left to right.
Typing while the dimension is selected replaces the measured value with your own text, for when the sheet disagrees with itself. Clearing what you typed puts the measured value back; there is no reset to find.
It cannot be click-placed. A measurement of nothing in particular is not useful, so it always takes a real drag.