Length

Two clicks give a straight measurement. Snapping catches the drawing's own corners and line ends; hold Shift to force horizontal, vertical or 45 degrees.

Why you would use it

The everyday measurement: how long is that run.

For example

What to do

1. Click one end.
2. Click the other.

Going further

Hold Shift to force it exactly horizontal, vertical or 45 degrees; it still snaps along that straight run, to a corner or line it meets. Snapping catches the drawing's own corners and line ends, so a pick lands on the corner rather than near it.

If you already use another program

In a CAD program: Distance between two points, but the result is kept as a line you can see, name and total.

In a building-model program: Measure, between two references: here the measurement stays on the sheet and goes into the take-off.

In a PDF markup program: A length measurement: two clicks, a labelled line.