A spec sheet tells you what to buy. Takeoff tells you how much. The two are linked through rooms, so a measurement entered once feeds every item in that room.
Measure the rooms
Rooms live on the Rooms page in the project sidebar. Add a room, give it a name that matches how you talk about it on site, and enter its measurements.
A rectangular room needs a length and a width. For anything that is not a rectangle, use the shape sketch: draw the outline as a polygon and the app computes the area and the perimeter from the points. A rectangle drawn as a polygon produces exactly the same numbers as a rectangle entered as length by width, so there is no penalty for using the sketch everywhere.
Link items to rooms
An item can name its room directly, and a section can set a room for everything inside it. When both are set, the item wins. That lets you put a whole Primary Bath section in the primary bath and still point one line at the linen closet.
Turn a measurement into a quantity
Open an item's drawer and expand the Takeoff disclosure. Takeoff computes an order quantity from three things: which room surface you are covering, a coverage rate, and a waste factor.
Category presets fill the sensible starting values. Floor tile defaults to the floor area with a tile appropriate waste percentage; baseboard defaults to the perimeter; paint defaults to wall area. Change any of them.
Takeoff does not silently write your quantity. It shows you the computed number next to the quantity the item actually carries, and flags drift when the two disagree. Applying it is an explicit action.
Apply it per section
Each section has a Takeoff summary showing every item with a takeoff configured, the computed quantity, the current quantity, and which ones have drifted. One action sets quantity from takeoff for the whole section.
This is deliberately a one shot write rather than a live binding. Your quantity field stays the authoritative number, so a supplier telling you the tile comes in full cartons does not get overwritten the next time somebody edits a room measurement.
No money is involved
Takeoff touches quantity only. Line totals are quantity multiplied by unit price, so the money flows through the existing rollups without takeoff having any opinion about it.