The phrase Graphisoft leaned on at the AIA Conference on Architecture & Design in San Diego on 11–12 June — “a common source of truth” — is not a marketing coinage. It is a fifty-year-old computer-science problem. Distributed-systems researchers gave it a rigorous shape in 2011, when Marc Shapiro’s team at INRIA formalised conflict-free replicated data types (CRDTs): the maths of letting many people edit the same state, offline, and merge without a referee. Every time our office and its Fachplaner touch the same model from three cantons, that is the problem we are living.

So when Graphisoft says its new open collaboration layer will keep “models, documents, issues and decisions synchronised across teams” — supporting five widely used interchange formats (IFC, BCF, PDF, DWG and RVT), with early access planned for later this year — we read it as a practice, not a press release. Sylwester Pawluk, the group’s VP of product management for collaboration, framed it, per AEC Magazine, as bringing “architects, engineers, builders, owners and operators into a common source of truth.” The honest question on our side of the desk: whose truth, and who owns it the hour a Wettbewerb model becomes the Ausführung model?

The second announcement matters more to a mixed-trade project than the first. An upcoming Archicad update adds a built-in connection to Autodesk Forma Data Management, letting teams exchange models and documents in native formats without leaving Archicad. Márton Kiss, Graphisoft’s chief product officer, called it a commitment to “open collaboration and customer choice.” Translated: parent Nemetschek Group is admitting the other half of your project team lives in Autodesk, and stitching a seam across the fence instead of pretending the fence isn’t there. A coordinated ecosystem update spanning five products — Archicad, BIMx, BIMcloud, MEP Designer and DDScad — lands in early October, alongside a browser-based, BIM-expertise-optional design-intelligence tool in early access the same month.

Here is what a fourteen-person studio actually takes from this. The week we finally trusted the IFC round-trip was the week we stopped treating the exchange format as a lossy afterthought and wrote it into the BEP. A vendor’s “common source of truth” is only as true as the discipline around it — LOIN agreed before kickoff, one named owner for the coordination model, IFC4 and BCF as the contractually canonical formats, issues closed rather than emailed. The platform does not hand you that; it only punishes you faster if you skip it.

Atelier: For a Büro adopting AI-flavoured collaboration this year, the real risk is buying the cloud and skipping the contract. The Monday move: write a one-page ownership clause into your next BEP naming who holds the master IFC4 file, who may merge, and which format is canonical when Archicad and Forma disagree — settle it before October’s early access lands, not after.

Hack: Count what survived the export before you trust anyone’s round-trip. Open the competition IFC and its re-imported twin, count the walls in each, and let the number — not the vendor — tell you whether the seam held.

import ifcopenshell
model = ifcopenshell.open("competition.ifc")
walls = model.by_type("IfcWall")
print(len(walls), "walls survived the round-trip")

Run it against both files; any mismatch in the count is the first agenda item of your next coordination meeting.

←TODAY: In 2026 the “single source of truth” is still a contract clause, not a feature — Graphisoft’s own layer supports IFC and BCF precisely because no one format has won. →3012: By the Zurich-3012 horizon the model outlives every vendor that ever hosted it; the office that documented its own exchange discipline still reads its files. Fulcrum: The platform only earns its keep for a practice that already knows who owns the model.

PAZ Takeaway: The gap this exposes is not tooling but the seam between Archicad and everyone else’s stack — exactly where the PAZ Grasshopper↔Archicad Library lives, personalising the round-trip and filling the parts the native Forma connection leaves thin. A practice like ours gains more from a documented, owned bridge than from a fourth cloud subscription.

Before you sign up for October’s early access, document your own IFC round-trip and measure its loss. Own the seam before you rent the platform.

Source: AEC Magazine — BIM / computational / AI tooling