A plan is a set of claims. This wall sits this far from the boundary. This room has enough window. This railing is high enough. This apartment has the area the schedule says it has. Someone checks each claim before the building is approved: a reviewer at the Bauamt, a cost planner, an engineer. They are the invisible people of every Baubewilligung. Our next Archicad Powersession starts from a simple idea: the model can check those claims before any of them has to ask.

The event page puts it in one line: Vom Werkplan-Marathon zum geprüften Plan. “Archicad Powersession – PAZ-BOX Kontroll” runs on Wednesday 18 November, 12:00–13:00, at PAZ Central in Zürich. It is free, lunch is included, and there are 20 seats.

The idea is older than the add-ons. Archicad goes back to 1984 and to Gábor Bojár’s Graphisoft in Budapest, and its long-standing idea is the Virtual Building: draw the building once as data, and every view of it is a reading of that data. A check is one more reading. If the model holds the railing, the facade and the zone, the questions an authority will ask already have answers sitting in the file.

Four claims, checked live

The 35-minute demo, “PAZ-BOX × Control”, covers four topics from the page.

Vermassen nach SIA 400. Dimensioning that follows the Swiss drawing norm. Our 5 October piece on SIA 400 in the Archicad template reported that the norm covers line types, scales, hatching, dimensioning and sheet titles. That was the template step. This is the checking step.

Normen, bevor die Behörde fragt. Railings, barrier-free design, building length and window area: the questions a reviewer tends to ask first.

Modellhygiene mit einem Klick. Skewed walls, open connections, duplicates and misplaced zones, the quiet faults that make every downstream number harder to trust.

Zahlen, die stimmen. Areas per SIA 416, the Wohnungsspiegel and costs, all read from the same zones.

The PAZ add-ons page lists the Control package as “all 7 checking tools and reports”, from ModelHygiene and Gebäudelänge to FensterFit for the 10 % window ratio and a SIA 416 cost calculator, ready for Archicad 28, 29 and 30 on Windows and Mac. One limit binds them all: a check reads only what the model says. A zone with the wrong category passes every test and is still wrong.

←TODAY: In 2026 railings, window ratios and SIA 416 areas are often still checked by hand, late, just before submission.
→3012: In Zurich-3012 a plan leaves the office with its own proof attached, and the authority reads the checks before the drawings.
Fulcrum: A check is only as good as the data underneath it. Clean the model first, then the proof is real.

Atelier: For a 12-person Zürich studio, the shift is moving the moment of truth: checking stops being a panic at the end and becomes a habit during the Werkplan phase. Any team adopting automated checks, or AI on top of them, needs zones and elements named consistently enough to trust. Monday move: choose one person to own zone categories in your template, and have them fix the uncategorised zones before anyone runs an automated check.

Hack: Count the zones your model actually holds, and compare that number with the rows in your apartment schedule. Graphisoft’s official Python API (pip install archicad) talks to a running Archicad session through its JSON interface. Five lines give you the count:

from archicad import ACConnection
conn = ACConnection.connect()
acc = conn.commands
zones = acc.GetElementsByType('Zone')
print(len(zones), "zones in the model")

If the count does not match the Wohnungsspiegel, you have found your first hygiene task, before any authority did.

The lunch hour itself

Arrival at 12:00, live demo 12:05–12:35, then the Zmittag-BOX and time to talk until 13:00. The session is in German, at Niederdorfstrasse 77, 8001 Zürich, near Rudolf-Brun-Brücke on trams 4 and 15. Bring a project file; over lunch we look at it together, and that half hour is usually where the real questions surface. It sits with our other hands-on dates on the PAZ workshops page.

Before 18 November, open your current Werkplan set and find the three numbers an authority would check first.