Measurement & takeoff

A measurement is a markup that knows what it is worth in real units. Everything on this page hangs off one idea: the page is in PDF points, the drawing is in feet or metres, and a calibration is the mapping between them.

Calibration#

ScaleCalibration carries:

Units are inch, foot, yard, mile, millimetre, centimetre, metre and kilometre.

Calibrating by hand. In the Measurements panel, choose Calibrate, pick two points whose real separation you know, and type that length. Anything works: a printed dimension string, a door width, the scale bar.

Calibrating from the file. A PDF may declare its own scale in a /Measure dictionary, and Redline adopts it — including the number format, which records the precision the drawing was authored at. A drawing that says quarter inches should read 4'-5", not 4'-4 15/16". That is not more precise; it is wrong about what the drawing claims.

Anisotropic scale. X and Y can differ, which is what makes civil profiles measurable. The Euclidean distance for an angled line is computed on the calibrated deltas, not on raw points, and areas use the shoelace formula over calibrated coordinates.

The scale cascade#

Scale resolves in three tiers, most specific first:

Region scale   →   Page scale   →   Set scale

That is what lets one sheet carry a plan at 1/8" and a detail at 1 1/2" without lying about either. Region Scale calibrates a rectangle of the page; Set Scale applies one calibration across every sheet in a set at once.

A measurement records which calibration it resolved against, so changing a page's scale updates the measurements that inherited from it and leaves alone the ones that did not.

Unit formatting#

Three styles, each with its own precision control:

Fractional precision runs from halves to sixty-fourths. The conversion rounds to the nearest fraction at that denominator, then simplifies by the greatest common divisor — and carries properly, so a value that rounds to a whole inch reads 12'-7" rather than 12'-6 16/16", and one that rounds up through twelve inches increments the foot.

showUnits controls whether symbols are appended. The Measurements panel's Precision dropdown shows the effective value and clears the file's declared precision when you set one explicitly; the global setting in Settings ▸ Units does not override a file that declares its own.

The measurement tools#

Labels recompute live. Drag a vertex and the number changes with it; change the page scale and every measurement that inherits it follows.

Beyond the base six:

• Dynamic Fill floods a bounded region — a room, a slab, a paved area — and produces its area without tracing the boundary by hand.
• Area cutout is a subtractive polygon: draw it inside an area measurement and its area is removed from the total, which is how a stair opening comes out of a floor slab.
• Spaces are named regions that group takeoff by room or zone, so quantities can be reported per space rather than per sheet.
• Auto-count finds repeated symbols on a page and places count marks at the matches.

Takeoff columns#

Every markup is a row in the Markups List, and measurements populate the takeoff columns:

Depth is what turns an area into a quantity: enter a slab thickness and Volume follows; enter a wall height and Wall Area follows.

Two things that figure is showing:

• Measurement is the general column. Whatever a markup measures, its quantity appears there in the unit its type calls for — an area in square feet, a length in feet and inches, a count as a tally.
• The per-type columns are sparse on purpose. Area is populated for an area and a dash for everything else. That is what makes a column sum meaningful: totalling Area totals areas, not a mixture.

Columns are chosen from the control at the left of the list header. The takeoff columns only appear there once the document actually has measurements — before that there is nothing for them to hold.

Rows sort, group and subtotal, and the grouping is what an estimator actually works in — group by Subject to get quantities per assembly, or by Space to get them per room.

Dynamic legends summarize the takeoff on the sheet itself, updating as the measurements change.

Measurements on paper#

Two behaviours differ between exporting and flattening, and the asymmetry is deliberate.

Export keeps the markups live. A round-trip save keeps every markup in the embedded record, so the reader can recalibrate and the numbers recompute. Baking the value into ink beside a mark that can still be recalibrated would create a second copy that goes stale.

Flatten bakes the numbers. A flatten destroys the live copy, so the ink is the only record of what was measured — and it carries the value.

When the units are not known, a flattened measurement gets no label rather than a guessed unit system. A sheet reading "40 SF" where it means square metres is not recoverable by looking at it.