Drawing · service journeys · to scale
A service blueprint gives every step the same width. An architectural section is drawn to scale — which is what lets a drawing be wrong about something.
A service blueprint is a diagram. Every step is a box of the same width, stacked into lanes that are ordered but not measured. Neither axis means anything, and a drawing whose axes mean nothing cannot be contradicted by the world.
An architectural section is a cut through a building, drawn to scale. Scale is not a style there — it is the whole contract. You can hold a rule against the paper and catch the drawing out. That is the property worth borrowing.
Put a service on those terms and the picture inverts. The drawing above is a data breach at the median durations recorded in the VERIS Community Database. Drawn as a blueprint it is five tidy boxes and the eye lands on containment, because that is where the work is. Drawn to scale, containment is a sliver and the drawing is thirty days of nobody knowing.
That is not a presentational difference. It is a different conclusion about where the problem is. The industry has built an enormous amount of tooling for the two days and comparatively little for the thirty — and the blueprint is part of how that happened, because it draws the two at the same size.
Two conventions carry most of the weight. Poché — the solid fill an architect uses for material the cut passes through — marks where the person actually is. In the breach section the person's own level is empty for the entire drawing, and you see that before you read anything. And the break symbol, which in drafting means "this continues beyond the sheet", here means this was never measured. The tool will not invent a dimension it does not have, so the step where someone is finally told is drawn broken. VERIS has no field for it.
The rest of the vocabulary is in CONVENTIONS.md, with what each mark is doing. A convention that stops carrying information should be removed rather than kept for the look of the thing.