Cutout

Subtracts an opening from an area you have already measured — a rooflight out of a roof, a window out of wall cladding. Select the area first. The opening must sit wholly inside it.

Why you would use it

So an opening is taken off the area once, properly, instead of being measured separately and subtracted by hand.

For example

What to do

1. Select the area you have already measured.
2. Pick the tool and click round the opening.
3. Double-click, or press Enter, to close it.

Going further

An opening has to sit wholly inside the area it comes out of. One that’s only partly inside is shown as not deducting, rather than deducting part of itself quietly.