Drawing change requests

NJS uses both Archicad and AutoCAD (Neil confirmed this on 13 Oct 2026). What can be automated depends on which package holds the drawing being changed, so each is set out separately below.

What the demo above is.A 2D DXF stand-in. DXF opens natively in AutoCAD and saves back to DWG, so for an AutoCAD drawing it is close to the real file edit. For an Archicad drawing it demonstrates the workflow (request, typed edits, check, issue), not the file edit: that happens inside the Archicad model, through Archicad's own API.

Archicad: what we can do

Route: a small agent on one Windows seat with Archicad open, signed in and licensed.

• Graphisoft's own JSON API (built into Archicad 30) reads elements, zones, properties and layouts. Its only writes are property values, classifications, layout settings, navigator items and attribute folders.
• The free Tapir add-on (MIT; release 1.7.0, 4 Oct 2026, has builds for Archicad 25 to 30) adds the edits we need: move, resize or flip a door or window (ModifyDoors, ModifyWindows), edit or create texts and labels, set the Project Info fields that title blocks read, publish a publisher set to PDF, save, snapshot to an archive, and reserve and send on BIMcloud Teamwork.
• Graphisoft's Public Archicad MCP Server (beta, Archicad 30, Collaborate or Max plans only) lets Claude query the model and make property and parameter batch edits with a preview-and-confirm step, plus Teamwork reserve and release, keynotes and menu commands.
• Archicad updates its own dimensions, schedules, sections and other sheets when an element changes.

Archicad: what we cannot do

• Run without a desktop. There is no headless or cloud Archicad: every route needs a licensed, signed-in Archicad running with the project open, and a cloud licence runs on one device at a time. We cannot edit a PLN file on our server.
• Move elements, edit text, publish or save through the built-in JSON API alone. Those need Tapir (or a C++ add-on).
• Rely on Graphisoft's MCP server for the edit itself: its published tool list does not include moving elements, editing text, publishing or saving, and it is not available on the Studio plan.
• Create a revision issue or revision change. Neither the JSON API, Tapir (which only reads revisions) nor the MCP tool list does it, so the Issue step stays a one-click human step in Archicad, or needs a C++ add-on.
• Change the model by editing a DWG exported from Archicad: that file is a copy, and edits never flow back to the PLN.

AutoCAD: what we can do

Routes: Autodesk's cloud with no desktop, or a small agent on a licensed AutoCAD seat.

• In Autodesk's cloud, with no desktop: the Automation API(Design Automation for AutoCAD, on Autodesk Platform Services) runs AutoCAD's core console with no screen. Our code, packaged as a .NET, AutoLISP or script bundle, edits the DWG (move blocks and lines, change text and title-block attributes, add revision clouds and revision rows) and plots the layouts to PDF; Autodesk also ships a ready PlotToPDFactivity. Files go in and out through signed URLs on Autodesk's storage, and our server signs in as an APS app (two-legged OAuth).
• Cost of the cloud route: 2 Flex tokens per processing hour once the free monthly cap is used (roughly US$6 an hour at the smallest token price), so cents per job. Pay as you go is offered in NZ, or prepay from 100 tokens.
• On a desktop seat: a small agent drives full AutoCAD through its .NET API, AutoLISP or script files, or runs accoreconsole (no window, but it still needs the activated licence on that machine).
• In our own code: read and write DXF, as this demo does. AutoCAD opens our DXF directly and can save it as DWG.
• Revisions on an AutoCAD sheet are drawing content (title-block attributes, a revision table, revision clouds), so code can bump them, as this demo does.

AutoCAD: what we cannot do

• Automate AutoCAD LT the same way. LT 2024 and later on Windows runs AutoLISP and script files, but has no .NET, ObjectARX or VBA. The cloud route does not depend on which AutoCAD NJS owns.
• Edit a DWG in our own TypeScript code. A DWG must first be converted to DXF, and DXF is a subset of DWG: proxy and AEC objects, dynamic-block behaviour, some annotative scales and fields can degrade. So a real DWG would be edited inside AutoCAD (cloud or desktop), not by our DXF code.
• Update other sheets automatically. AutoCAD is 2D drafting: a moved door means fixing the wall gap, the dimensions and every other sheet that shows it, and each must be checked.
• Keep the file on NJS's drive during a cloud job: the DWG is uploaded to Autodesk's storage for the run. No public automation API was found for AutoCAD Web.

What the three sample requests map to

Both packages

• The tool proposes; a technician approves.Nothing is saved to the master or issued until a person has checked the before and after. These are consent documents issued under the practice's name, so liability stays with the practice, and some changes need a council amendment or minor variation.
• Snapshot first. Every job starts with a copy (an Archicad archive, or a copy of the DWG) so a change can be rolled back.

Questions for Neil

• Which package holds which drawings? In particular, does the consent set live in Archicad, in AutoCAD, or in both (for example AutoCAD for older jobs or consultant files)?
• Which versions and plans? The Archicad version and plan (Studio, Collaborate or Max), and AutoCAD or AutoCAD LT, which year.
• Where do the files live? Archicad on BIMcloud Teamwork or a PLN on a shared or synced drive, and the DWGs on which drive?
• Is there a spare seat (Archicad, AutoCAD or both) an agent could use? Whether a seat may run unattended is a licence question for Graphisoft, Autodesk or the NZ reseller, in writing.
• Would sending a DWG to Autodesk's cloud for a job be acceptable to you and your clients?
• Could we have one real project from each package (PLN, DWG, PDF set, past change emails) under NDA for the pilot?

Known limits

• Tapir is a community project; its build must match the Archicad version and regressions happen (issue #759). Pin versions and re-test on every update.
• Nothing on this page has yet been run against Archicad, AutoCAD or Autodesk's cloud. The pilot would do that first.

Source: our research note docs/research/cad-automation-options.mdand its correction of 13 Oct 2026, which cite Graphisoft's and Autodesk's documentation and the Tapir repository. Suggested pilot: two to four weeks on one workstation per package, measured on 20 to 30 of your past change emails.

What this proves, and what it does not

The sample house is ours, generated in code, so there are no licence questions and the layers are clean. Everything runs in TypeScript on the server: no Python, no CAD software, nothing installed on your machines.

Proves

• An email becomes a short list of typed edits, chosen by Claude from a fixed set, against ids in the drawing, not by guessing from pixels.
• Every edit is validated (ids exist, 100 mm jamb clearance, no overlaps, sensible widths) and failures are shown, not fixed silently.
• Ambiguous requests come back as questions; text in the email cannot change the rules (the prompt-injection fence).
• The edit is applied to a copy, with a before/after, the change in red, the old position ghosted and a revision cloud.
• Re-plot and re-issue are automatic: before/after DXF, a revised PDF with a revision stamp, and a transmittal, but only after a person ticks the check.
• Real DXF files can be read: open one of yours below (saved from AutoCAD or exported from Archicad) to see its layers, entities and text.

Does not prove

• That the edit works inside Archicad, with its model-wide effects on sections, elevations, schedules and other sheets.
• That it works on a real AutoCAD DWG. The demo writes DXF, which AutoCAD opens, but a DWG with dynamic blocks, xrefs or AEC objects would be edited inside AutoCAD (on a seat or in Autodesk's cloud), and that has not been run yet.
• That it works on NJS's real files, layer names and title blocks, or with Teamwork, BIMcloud or a synced drive.
• Integration with Archicad's revision manager.
• Success rates on real, messy emails: three samples are not a measurement. The pilot would measure 20 to 30 past requests.
• Full 2D drafting: this sample has one associative dimension, simple door symbols, and DXF (not DWG) output.

Live plans call Claude with the drawing inventory and the email text; the Claude API does not train on API data by default. With no API key, the three samples replay recorded answers from one real run, labelled “Recorded”.