Understand · Going further · 3 min
The drawing's layers and your markup layers
Two different things share the word layer. Keeping them apart is what stops a hidden layer from changing a quantity.
A PDF can carry its own layers (optional content), usually put there by the CAD program that made it: structure, services, dimensions. Switching one off hides it on the sheet. You can do that here, and it never changes a quantity, because quantities come from your measurements, not from what’s visible.
Your markup layers are sets of your own markup. A layer may take everything (a note, a cloud, a measurement). A take-off group is different: it’s a line of a bill, so only measurements may join one.
Hiding anything is about looking. A hidden measurement stays in the register, stays in its group, and counts towards every total. The only thing that leaves a measurement out of a bill is the flag measured but not recorded, which belongs to the measurement, not to a layer.