A way to operate C3 by describing what you want. You type or dictate a request — “Draw a 6-inch flange with eight 0.400 holes on a 4.75 bolt circle and give me a hole table” — and the Assistant calls C3’s own drafting tools to build it. The result is ordinary C3 geometry on your layers, in your file: select it, stretch it, dimension it, print it. It is not an image generator. Twenty-four requests and the drawings they produced →

C3 itself never needs the internet, and the Assistant is switched off until you turn it on. When you enable it you choose the model: your own Anthropic or OpenAI account (your request and a description of the drawing go to that provider under your key), or a private model endpoint on your own network, in which case nothing leaves your machine. C3 tells you what is sent before you enable it, and the Support Log records every call.

Yes. C3 Secure Enterprise points the Assistant at a customer-controlled endpoint — your organization’s own model server through a supported API-compatible interface — with the external providers disabled. C3 shows the active policy in plain words, tests the connection against the real tool catalog, and logs the host of every turn. It has been demonstrated with Wi-Fi switched off and a locally hosted model running on the same Mac. A managed-preferences lock for Jamf, Kandji and Intune fleets is in development. Contact Tetra720 for enterprise terms.

You do, directly, and only if you use it. The Assistant runs on your own API key, so the provider bills you at their published rates; C3 shows the cost of each request in the panel. The short briefs on the Assistant page ran between about twenty and thirty-five cents each on Claude Sonnet 5. There is no Tetra720 markup and no subscription.

Everything it does in one request is one step on the undo stack: one Cmd+Z removes all of it. It works through the same undo-wrapped operations the menus use, so it cannot bypass C3’s safety nets, and the dimensions it places are associative and measured from the geometry — it cannot type a value that lies.

C3 is a self-contained application with no runtime dependencies. No licensing servers, no dongles, no cloud validation. Your software keeps working forever, even if we shut down tomorrow. (DWG import optionally uses the free ODA File Converter as an external bridge; C3 itself runs without it, and every other format — DXF, Eagle, Gerber, SVG, PDF, .cadd — is handled natively.)

Your drawings are yours. C3’s native .cadd format is plain JSON — human-readable, inspectable with any text editor, and trivially parsed by any programming language. You can also export every drawing to DXF (R12, round-trip tested with AutoCAD, DraftSight, and LibreCAD), SVG, PDF, or Gerber RS-274X. No DRM. No encrypted container. No proprietary blob. If you ever move to another CAD program, your work moves with you.

Contact us for a personalized demo. We'll walk through your specific workflow and show you exactly how C3 handles your use case.

Every feature is a labeled button on one of eight one-key side menus, and the program tells you the next click at every step (spoken, if you like). The complete User Guide is built in: press ? to open it, or Cmd+/ to open it already scrolled to the menu you have open and the button you last clicked — it works inside popups and text fields too. You can also export the guide as HTML or print it as a PDF.

Import: DXF (R12–R2018+); DWG, with paper-space title blocks and modified dynamic blocks intact; whole DWG symbol libraries; SVG artwork at true size; KiCad schematics, symbols and footprints; Eagle .BRD boards; PDF pages and PNG/JPEG images as scaled underlays; survey points from CSV; room and surface scans from the C3 Room Scanner for iPhone; and legacy CADD/300 (.C95) files. Export: DXF and DWG for CAD exchange; Gerber RS-274X and Excellon drill for PCB fabrication; KiCad-format and CSV netlists; SVG with real inch units for laser and vinyl cutters; EPS (Encapsulated PostScript) at exactly 1:1 with no background, the vector file screen printers and sign shops ask for; and print or PDF at exact scale. Native format: .cadd, readable JSON.

Yes — natively, on the canvas. Attach attribute data fields (designator, part number, rating…) to any symbol, and Extract Attributes → Table builds a live table from every placed instance: a grouped BOM with quantity counts, or a per-instance schedule. It’s a real C3 spreadsheet table — formulas, CSV export, printing — and one click refreshes it as the drawing changes. Attributes also round-trip with AutoCAD via DXF (ATTDEF/ATTRIB).

No. C3 is native macOS only (Apple Silicon and Intel). This isn't a port — it's designed specifically for Mac using SwiftUI and CoreGraphics.

No. Ever. We believe professional tools should be owned, not rented.

Every Gerber file passes UCAMCO validation. We've verified against Hardy's production boards that have been successfully manufactured for decades. Zero tolerance for errors.