Every plan set that crosses a Swiss desk is read against the same convention. SIA 400, “Planbearbeitung im Hochbau”, is the norm for how building plans are prepared and exchanged between architects, civil engineers and building-services planners. According to the SIA 400 text hosted on the HES-SO Cyberlearn server, its technical means include line types, plan content, CAD drawing and dimensioning (cotation in the French edition). Its stated aim is plans that help a building reach its intended quality while keeping to deadlines and construction costs.

On Wednesday 7 October 2026, from 11:30 to 12:00, we take one of those means and turn it into a single move. The ARCHICAD POWER SESSION – SIA400 runs on Zoom, in German, for CHF 0. The event page puts the whole promise in four words: “Klicken. Vermasst. Nach Norm.”

Why dimensioning, of all the norm’s chapters

Dimensioning is where a design change costs the most redrawing. One moved wall can break a chain in the plan, the section and the facade. The person who catches it is usually a drafter late in the day, the unnamed author behind every plan set that ever cleared a Baueingabe. Automating the chain does not replace that care. It gives them back the hours.

The trade-off is plain: a one-click chain is only as good as the model beneath it. A wall drawn off-axis in the model will be dimensioned faithfully off-axis on the sheet.

Thirty minutes, three moves

According to the agenda on the PAZ event page, the half hour runs like this:

• 11:30 — “Ein Klick — das ganze Geschoss.” One click dimensions a whole floor plan: four dimension lines, continuous interior dimensions, and height levels at every floor (OK fertig, OK roh, UK).
• 11:40 — “Schnitt und Fassade — der Plan ändert sich.” Continuous dimension chains in sections and facades that hold as gebundene Masse when the design changes.
• 11:50 — “Deine Fragen, live beantwortet.” Live Q&A, and you can bring your own project.

The demo runs on a real project example, so you can check the claim on screen step by step. Registration is free via the PAZ booking page. The page addresses the session to PAZ-BOXers, alongside Architekt:innen, Wettbewerbsteams, Entwurfsabteilungen and offices focused on Ausführung.

The series runs on one idea: one Swiss norm, one automated move. SIA 358 came on 30 September; SIA 400 follows. One note on scope: SIA 400 governs how plans are worked up and dimensioned, while CAD layer organisation belongs to the separate SIA-Merkblatt 2014, as Swiss cantonal CAD guidelines show by citing the two side by side. This session stays on Vermassung.

←TODAY: Swiss plan sets are still checked chain by chain against SIA 400, by eye, after every change.
→3012: In Zurich 3012 the drawing is a view of the model, and the norm is a rule the model runs, not a binder on a shelf.
Fulcrum: Bound dimensions are where a norm stops being read and starts being executed.

This is where the agents-and-tools conversation gets honest. Before any AI assistant steers Archicad, an office needs deterministic tools it can trust: a dimension chain either closes or it does not. Repeatable, checkable Archicad automation is the floor an agent stands on.

Atelier: For a small studio heading toward a Baueingabe, dimensioning swallows the end of every change cycle, and it is the first task worth automating before handing anything to an AI assistant, because the result is easy to verify. The Monday move: take one finished storey from a live project, list every dimension chain your office standard requires on it, and keep that list as the test sheet for judging any automated dimensioning.

Hack: Prove that a dimension chain closes before the plan leaves the office. The segments of a chain must add up to its overall dimension; if a wall moves and one segment is not updated, the sum drifts. Paste the wall-axis coordinates of one storey from a schedule export and let the assert catch the error:

axes = [0.0, 3.80, 7.55, 11.30, 14.90]  # wall axes, metres
chain = [round(b - a, 3) for a, b in zip(axes, axes[1:])]
total = round(axes[-1] - axes[0], 3)
assert abs(sum(chain) - total) < 0.001, "chain does not close"
print(chain, total)

Bound dimensions close by construction. The script tells you whether yours already do.

Open the last plan set your office sent out, pick one storey, and check that its outer chain adds up.