On Thursday, 29 October 2026, we hold the fourth PAZ-Rhino session, PAZ-RHINO-IV, and it is about PAZ-RIA. PAZ-RIA runs Rhino and Grasshopper inside Archicad: scripts run without leaving the model, data comes straight out of the project, and geometry and 2D drawings go back in as native Archicad elements. This session covers the part every office skips and then pays for later: the setup underneath. Rhino, Grasshopper and Archicad have to agree on units, tolerance, template and version before anyone writes a single component.

The tools we stand on come from somewhere, and we name where. Rhino is the work of Robert McNeel & Associates. Grasshopper began as David Rutten’s work inside McNeel. McNeel also built Rhino.Inside, the technology that lets Rhino and Grasshopper run inside other programs, and PAZ-RIA runs on it. Over the years Grasshopper turned parametric design from a research topic into something a 12-person studio uses every day. As our 6 October PAZ-Rhino announcement reported, Rhino 8 now ships a CPython 3 script component. Office scripts can live directly on the canvas instead of in someone’s private folder. Our Back-to-Work Camp piece made the wider point: most methods now reshaping the drawing board are decades-old research that has only recently become cheap enough to run inside a working office. That is the thread Dr. Mikhael Johanes, a Design++ postdoctoral fellow at ETH Zurich, opened in his keynote at our 2–4 July 2025 KI Summer Camp. It is also why a setup session makes sense now and did not five years ago: the scripting host is standard, so the setup is the part that still varies from office to office.

What the launch showed

We showed PAZ-RIA in public for the first time at our second PAZ-Rhino Live on 15 October. A Grasshopper script placed a Voronoi beam structure on a slab and sent it into Archicad as native beams. When we re-ran the script, the same beams moved to their new position instead of piling up as copies. That is what makes a live link worth having, and it only holds when both programs agree on the setup first. An earlier exchange test on 26 August taught us the same thing: the geometry crossed cleanly, the extra data riding on it did not. The lesson we took away: do not ask the exchange to carry meaning you can rebuild on the other side. PAZ-RHINO-IV starts from that lesson. We set up the link so that geometry is the thing that travels, and the office rebuilds the meaning deliberately.

Here is the trade-off, stated plainly. A live connection saves hours on every design iteration. But it ties two programs together, and a mismatch in units or tolerance upstream shows up as silently wrong elements downstream.

←TODAY: Rhino 8 runs CPython 3 on the canvas, and Archicad accepts native elements from Grasshopper.
→3012: Zurich offices treat the bridge between programs as shared infrastructure, maintained like a water main.
Fulcrum: The setup that nobody sees decides whether the script everyone sees can be trusted.

Who it is for

The session is for BIM coordinators, computational designers and engineers who already open Rhino and Archicad in the same week and are tired of rebuilding one model by hand in the other. It follows the method of our Building System Specialist Title. According to the BSS Title page, that is a five-month mentorship at six hours a week, and it has certified 39 specialists; Edition XIV began on 1 September 2026. That method puts the foundations first, and only then the clever tools. It is the ground under any later Archicad automation, including PAZ-RIA itself, which ships as a new PAZ-BOX add-on in all three packs; PAZ-Rhino licence holders get their own version.

Atelier: An office that adopts a Grasshopper-to-Archicad link without a written setup ends up with one person who knows why it works, and that person is a bottleneck. Monday move: write a one-page setup sheet with the model units, the absolute tolerance, the Archicad template and the Rhino version, and pin it next to the shared project folder.

Hack: Check that your Rhino file is ready to cross before you connect anything. Paste these lines into a Rhino 8 Python 3 script component. The component reads the document’s unit system and absolute tolerance, converts the tolerance to millimetres, and flags any file looser than 1 mm, the kind that drifts once it reaches Archicad’s project units:

import Rhino
doc = Rhino.RhinoDoc.ActiveDoc
units = doc.ModelUnitSystem
tol_mm = doc.ModelAbsoluteTolerance * Rhino.RhinoMath.UnitScale(units, Rhino.UnitSystem.Millimeters)
print("%s | tol %.3f mm | %s" % (units, tol_mm, "ready" if tol_mm <= 1.0 else "fix setup first"))

Run it on the last three files your team shared. Whichever one says “fix setup first” is the file to bring on 29 October.

Full session details and the sign-up path are on our workshops page. Before Thursday, run the check, note which file failed, and bring it with you.