How to calibrate scale on any PDF (even when there's no scale bar)

A 6-minute guide to two-point calibration, scale verification, and what to do when the architect didn't include a scale bar.

Scale calibration tells Bedrock how many inches on the PDF equal one foot in real life. Without it, every measurement is in screen pixels — which is to say, useless.

1. Find a known dimension. The longest one you can find — usually a column gridline spacing on a structural plan. 30'-0" is better than 5'-0" because the calibration error compresses over a longer distance. 2. Click 'Set Scale' in the toolbar. 3. Click the start of the dimension. Click the end. Bedrock asks you what that distance represents in real life. 4. Type the dimension. Use feet-and-inches notation: 30', 30'-6", or 366in. Bedrock parses all of them. 5. Verify. Pick a different known dimension on the same sheet and measure it. If it reads correctly, your scale is right.

A column grid with dimensions at the gridlines A door or window with a known width (3'-0" is the most common) An ADA parking stall (8'-0" wide, 18'-0" deep) A truck dock door (typically 9'-0")

Bedrock can calibrate per sheet. Different sheets in the same set are often at different scales (the floor plan at 1/8" and the wall section at 1/2"). Calibrate each sheet you'll measure on.

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