AMFLOW PR · calibrated from a known length

Photo Caliper

Click two points across something whose size you know, type that size, and everything you measure after that comes back in millimetres. The four photos Ewan sent are loaded; the 30 mm hole spacing in them is the one dimension three sources agree on, which makes it the calibration to use.

scroll to zoom · drag to pan · click to place

Image

1 · Scale

not set — click two points

Calibrate on something the same distance from the camera as what you're measuring. Anything FARTHER away than the reference reads short. On this guard that cost 12 mm: the 30 mm washers sit at the near end, the far hole sits ~45 mm lower, and a true 220.7 projected as 208.

2 · Measurements

Whatmm

PR — what's known

Pair spacing30.0 ✓
Span, Ewan chord210
Span, Ewan arc220
Span, skid CAD220.88
Offset, Ewan8
Offset, skid CAD10.68
Offset, in the file9

Depth error beats every other error here. Measured against the 30 mm washers this guard's hole span read 208.2, twice, from two photos — and it is really 220.7, confirmed by CAD and by a slicer. The whole 12 mm gap is one cause: the far hole sits lower than the reference, so it projects small. Use this for features lying in ONE plane at ONE depth — a hole offset, a boss diameter, a width across a flat pad. The moment your two points sit at different heights on a curved part, the number is short and you will not be able to tell by looking at it.