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Linux CAD · Free Community license · Free Parameter LLC

Cadnat: natural language into plans.

Full construction sets you can open in any commercial CAD program, drafted on your own Linux machine.

Your DWGs stay off the cloud.* Real files on your own hard drive that load instantly.

Describe the job in plain words. Cadnat drafts the set: sheets on paper-space layouts, real layers, associative dimensions, your title block. You get DXF, a vector PDF set and a 3D model you can cut and measure.

Linux download: coming soon See phone to plans
  • DXF R2010 / R2000
  • DWG via LibreDWG add-on
  • Vector PDF sets
  • STEP / IGES
  • Arch · Debian/Ubuntu · Fedora
Illustration of a deck framing sheet A 16 by 12 foot deck framing plan with joists at 16 inches on center, a beam on three posts, stairs, dimensions, a section callout and a title block labelled sheet S-1. FIRMYOUR FIRMLOGO HERE PROJECT12x16 DECK SHEET TITLEFRAMING PLAN SCALE1/4" = 1'-0"DRAWN BY: CADNAT CLIENTCLIENT NAMEDATE: 2026-10-04 SHEETS-1OF 4 EXISTING HOUSE / LEDGER 2x10 JOISTS @ 16" O.C. (2) 2x10 BEAM STAIRS DN AS-2 16'-0" 12'-0" N
Illustration of a framing sheet layout. Real sets come from your parameters.

The difference

Real plans. Not pretty pictures of them.

Plenty of tools turn finished drawings into pretty pictures. Cadnat goes the other way: it drafts the drawings themselves, as a plan set that a builder, an inspector or another drafter can open in commercial CAD software and keep working on.

What Cadnat hands you

  • Sheets on paper-space layouts, with viewports at standard scales
  • Layers, linetypes and lineweights that plot the way they should
  • Associative dimensions in feet-inches with fractions, or metric
  • A title block with your firm, project, client, drawn-by and date
  • DXF you can send to anyone, plus a vector PDF set
  • A 3D model page with section, measure, select and walk tools

What it is not

  • A rendering service that makes pictures of plans you already paid for
  • A cloud app that keeps your drawings on its servers
  • A viewer that can only look at other people's files
  • A seat you rent forever just to open your own work

Cadnat Plans · phone to plan set

Tell it the job. Get the plans.

Cadnat Plans is an Android app paired with a plan server on your own Linux PC. Type or dictate the request on site, and the PC drafts the set. When it finishes, the files themselves download to the phone over your encrypted link. Never as a public link.

Demo video coming soonFrom a phone request to a full plan set, start to finish.
From a typed request to plan.pdf, model.html and params.yaml on the phone.
Short coming soonDictating a deck request on site.
Dictate it. Check the title block. Send.
Short coming soonCut a section, measure it, tap Draft.
Cut a section in the 3D model and get a PDF + DXF section sheet back.

How it works

Your phone talks to one machine: yours.

Your phone and your PC talk over a private, encrypted link between the two. Inside it, the Cadnat plan server answers only your paired phone, and only for plans.

  1. Ask

    Type or tap the microphone in Cadnat Plans. Fill the title block once (firm, project, address, client, drawn by); the app remembers it. Add your logo and a client logo if you like.

  2. Send privately

    The request travels over the private, encrypted link to your PC, inside TLS 1.3 to a server key pinned in the app. The phone proves who it is with its own device key on every connection.

  3. Draft on your PC

    The plan server queues the job. An AI pipeline on your PC picks a generator and writes the parameters inside a sandbox, and the generators draft the set offline. An empty viewport fails the job.

  4. Files back, not links

    plan.pdf, model.html and params.yaml come back over the same encrypted connection, each checked by SHA-256 on the phone. Open, share or save to Downloads.

Keep drafting from the model

The 3D page opens in the app: orbit with one finger, pinch to zoom. Place a section plane or a section box, look straight at the cut, tap two points to measure. Tap Draft and the PC sends back a section sheet as PDF and DXF, as a new job.

Nothing to type to connect

Your PC builds the app with its address, pinned key and your phone's own secret compiled in. With the private link up, open Cadnat Plans and the chip says Connected. Lost the phone? Revoke its key from the PC in one command.

Features

CAD that drafts the way a good drafter would.

A native Qt 6 application for Linux with the drafting conventions you already know, plus generators and natural language on top.

Natural language

Say what you want drawn

Type draw a rectangle 30x50 at 4,5,7 on the command line, or ask the Assistant for a 20 by 30 ft shed floor with a door opening on a new layer. It works through the same tools you use, lists every step, and undoes the whole turn in one click. Run it on a local model and nothing leaves your machine.

Generators

Whole sets from parameters

Deck, bath, kitchen and tile generators build complete sets. For a deck: joists, beam, posts, footings, decking, guards, stairs and design load. Every parameter is a form field with ft-in input, ranges and typical US residential defaults, IRC-based where a code limit applies.

Drafting

The tools you expect

Command line with classic aliases (L, PL, C, TR, EX, F), relative and polar input, object snaps, ortho and polar tracking. Blocks with attributes, xrefs, hatches, linetypes, multileaders and every common dimension type.

Sheets

Paper space done properly

Layouts and viewports at standard architectural and engineering scales, per-viewport layer freeze, annotative text, and vector PDF plots with true lineweights. ARCH D, ANSI B and ISO A1 starters with title blocks.

QA

Sheet checks before it leaves

cadnat-cli check flags overlapping text, text off the sheet, small plotted text, annotation-scale mismatches, empty title-block fields and leftover scratch layers. Rules are editable and cite public standards.

3D

Solids and real sections

Direct modeling on Open CASCADE: extrude, push/pull, loft, revolve, booleans, fillet and chamfer. Section planes and boxes with hatched caps, 2D section drawings with plan callouts, BIM-lite data and CSV schedules.

Site

Real-world context, license-free

Search a place, pick from about 9,800 coordinate systems through PROJ, import terrain and OpenStreetMap layers (buildings, streets, water, parcels where mapped) onto your drawing.

Files

Files that travel

DXF R2010 by default with an R2000 option, checked with an independent DXF reader. DWG through the free LibreDWG add-on. STEP and IGES, PDF and SVG. Image to DWG traces a logo into real geometry.

Linux

Native Linux, not a port

A native Qt 6 app, at home on Wayland. Runs on Arch, Debian/Ubuntu and Fedora.

Privacy and security

Your plans stay yours. Your DWGs stay off the cloud.*

Real files on your own hard drive that load instantly. There is no Cadnat server in the middle: your sets are drafted on your PC and delivered only to your paired phone, over a private, encrypted link between the two. No upload, no share link, no account with us to hold your files.

Most contractor features work completely offline. Drafting, generators, plan sets and DXF/DWG export run on your own machine with no internet. AI requests to a hosted model, map and terrain lookups, and the link to your phone need a connection.

“Save your tokens, bro.” Drafting, generators, sheet checks and exports run as plain code on your machine, so they don't burn a single AI token. Only plain-English requests to a model do, and with a local model those are free too.

Security controls of the Cadnat Plans remote plan server
LayerWhat it does
NetworkThe server listens only on your PC's address on the private link between your phone and PC, and does not start without it. No public port, no LAN exposure.
TransportTLS 1.3 only, inside the private, encrypted link. The app trusts no certificate authority: it accepts exactly one pinned server key and drops anything else before a byte of data is sent.
Device authEach phone has its own 32-byte secret and answers a fresh challenge on every connection (HMAC-SHA256). Revoke or rotate any phone from the PC.
CapabilitiesSeven operations, nothing else: ping, submit, list, watch, fetch, cancel, and one allow-listed follow-up action. No shell, no file paths, no file listing. Each phone sees only its own jobs.
SandboxThe AI step and the generators run inside the job folder only, with no network for generator commands, and with your keys, configs and other projects out of reach.
LimitsOne job at a time, 30-minute timeout, 30 plan jobs per day, strict size and type checks on uploaded logos.
ResultsSent as files on the same connection with size and SHA-256, verified by the app. The 3D page makes zero network requests.
AuditEvery request and refusal goes to a local audit log on your PC. No secrets are ever logged.
About the AI step. The plan server runs its AI pipeline on your PC, in a sandbox. If you bring your own model hosted by a third party, your request text and the parameters it writes are processed by that provider under your own account and its terms. Plan files (PDF, model, DXF) are produced and delivered on your own machines. The desktop Assistant can run entirely on a local model.

Your AI, your call

Bring your own model.*

Already have an AI assistant you like? Hook it up to Cadnat and let it run the drafting. Tell it “draw a 12x16 deck off the back door, then export the plan set” and it works the same tools you would, on your own PC, and every change can be undone.

  1. Use your own model inside Cadnat

    The built-in Assistant runs on a local model on your PC, or on a hosted model from a provider you pick, with your own API key. Your pick, your bill.

  2. Or bring your own assistant

    Open Cadnat and it starts a private agent link on your own computer, with a fresh access token every time it starts. The Cadnat CLI (cadnat-cli) picks that token up, so your assistant signs in without an account or a password. It has to run on the same PC.

  3. Tell it the job

    Your assistant drives Cadnat through cadnat-cli: drawing commands, the deck, bath, kitchen and tile generators, sheet checks and PDF plots. The status bar shows who is driving, and one click disconnects it.

# name your assistant, then check the link
$ export CADNAT_CLIENT=my-assistant
$ cadnat-cli status

# run the deck generator: 16 ft x 12 ft (inches)
$ cadnat-cli json '{"cmd":"tabs","op":"gen_panel","name":"deck",
    "set":{"deck.width":192,"deck.depth":144},
    "generate":true,"wait":true}'

# check the sheets, then plot one to PDF
$ cadnat-cli check --json
$ cadnat-cli layout list
$ cadnat-cli plot S-1.pdf --layout S-1
Real cadnat-cli commands. Your assistant sends the same ones. Sheet names depend on the set; layout list shows them.
For programmers. The agent link is newline-delimited JSON over TCP, listening on 127.0.0.1 only (port 47800 by default). Each request carries the per-session token from ~/.local/state/cadnat/agent.json (mode 0600). Every change is one undo step. cadnat-cli is Python 3 with the standard library only, and cadnat-cli json '{...}' sends any raw call. Generator forms are JSON Schema (python -m gen deck --schema), so an agent can fill them from plain English.
Coming soon MCP server. MCP (Model Context Protocol) is a standard way for AI assistants to use tools. Cadnat does not ship an MCP server yet. When it does, assistants that speak MCP will plug in without glue code. Today, connect through cadnat-cli or the agent link. Roadmap, not a dated promise.

Cadnat drafts and stores your plan files on your own machines. If you connect an AI model hosted by a third party (bring your own model), the text of your requests and the context needed to answer them (such as parameters and a drawing summary) are sent to that provider and are governed by its terms; Free Parameter LLC is not responsible for third-party services. Exclusions apply; see Privacy.

What it drafts

Decks, baths and kitchens today. Whole houses next.

Generators are parts of one plan set. Here is what drafts today, and what is on the drafting board next.

Today available

  • Decks: joists, beam, posts, footings, decking, guards, stairs and design load, fitted to ground you pick on a terrain surface
  • Baths: room, door, tub or shower, vanity, toilet, mirror, soffit, lighting and tile
  • Kitchens and tile layouts
  • Section sheets from any cut in the 3D model, as PDF and DXF
  • Title blocks with your firm and client logos on every sheet

Coming next roadmap

  • Foundations: 8 ft poured wall or slab on grade, with French drain
  • Floor framing by level (lower, 1st, 2nd, 3rd), joist direction respected, finish floor
  • Bedrooms sized to square-footage targets
  • Windows: double hung and single hung, with mullion and SDL options
  • Doors: French inswing and outswing doubles, sliding glass in XO or OX
  • Stairs with handrails and guards
  • Garages: attached or detached, 1 to 3 car
  • Whole-house sets, starting with a regenerable example house

Roadmap items are plans, not dated promises.

Cadnat drafts; it does not stamp. Defaults are a starting point, not an engineering approval. Check your local code and get a licensed professional where your jurisdiction requires one.

Pricing

The CAD is free. Pay for plans from the job site.

The Cadnat desktop app is free to use with the Community license. Subscriptions fund the phone app, the plan server, new generators and real support.

Community

The full desktop CAD app. Free to use, for anyone on Linux.

$0forever
Free license
  • Cadnat desktop app, free Community license
  • 2D drafting, paper-space layouts, dimensions, hatches, blocks, xrefs
  • 3D solids, section planes, BIM-lite schedules
  • Natural-language command line and Assistant (works with a local model)
  • Generator panel: deck, bath, kitchen and tile
  • DXF, STEP, IGES, PDF and SVG; DWG with the free LibreDWG add-on
  • Most contractor features work completely offline: drafting, generators, plan sets, DXF/DWG export
  • Community support on the issue tracker
Linux download: coming soon

No account, no card.

Most popular for builders

Pro

Plans from the job site. Your DWGs stay off the cloud.*

$29/ month
or $290/year billed annually
  • Everything in Community
  • Cadnat Plans Android app, built and paired for your PC
  • Remote plan server installer, setup guide and updates
  • 3D model page with section, measure, select and walk tools
  • Section sheets from the phone (PDF + DXF)
  • House generator packs as they ship
  • 1 plan server, up to 2 paired phones
  • Email support, 2 business-day response target
Pro checkout opens soon

Billed by Stripe. Cancel any time.

Builder

For small crews and drafting offices that share one plan server.

$89/ month
or $890/year billed annually
  • Everything in Pro
  • Up to 5 paired phones, each with its own key you can revoke
  • Your firm's title block, logo and layer standards set up for you
  • Sheet-check rules tuned to your office
  • One 60-minute onboarding call
  • Priority email support, 1 business-day response target
  • Early access to new generators
Builder checkout opens soon

Billed by Stripe. Cancel any time.

Compare plans in detail

FAQ

Questions builders ask

Will the files really open in my commercial CAD program?

Cadnat writes standard DXF (R2010 by default, R2000 if you need it) with layers, blocks, dimensions, multileaders and paper-space layouts, and checks its output with an independent DXF reader. DWG is available through the free LibreDWG add-on. Everyone can open the vector PDF set.

Is it really free?

Yes. The Community license lets anyone use the Cadnat desktop app at no cost, with no account and no card. Cadnat itself is proprietary software from Free Parameter LLC. Paid plans cover the Cadnat Plans phone app and remote plan server, generator packs, setup and support.

Do my drawings go to the cloud?

No. Your DWGs stay off the cloud.* Real files on your own hard drive that load instantly. Your PC drafts the set and sends it straight to your paired phone; there is no Cadnat server in the middle.

Does Cadnat work offline?

Yes, for most of the work. Most contractor features work completely offline. Drafting, generators, plan sets and DXF/DWG export run on your own machine with no internet. AI requests to a hosted model, map and terrain lookups, and the link to your phone need a connection. DWG export uses the free LibreDWG add-on, which also runs locally.

How does my phone connect to my PC?

Over a private, encrypted link between your phone and your PC. Inside it, the app accepts only TLS 1.3 to the server key pinned in it, and each phone proves who it is with its own key. Your setup kit walks you through it. Teams that already run Tailscale can use it as an optional networking add-on.

Which phones work?

Android 14 or newer. The app is installed from an APK your own PC builds (sideloading). There is no iPhone app yet.

Does an AI see my drawings?

The AI pipeline runs on your PC, in a sandbox limited to the job folder. If you point it at a hosted model, your request text and generated parameters go to that provider under your account; the plan files are produced and delivered on your machines. The desktop Assistant can run fully on a local model.

Are the plans code-approved or stamped?

No. Cadnat is drafting software. You, or the licensed professional you work with, stay responsible for structural design, code compliance and permits. Generator defaults are typical US residential values, IRC-based where a code limit applies, and you should check them against your local code.

Mac or Windows?

Cadnat is Linux-first: a native Qt 6 app for Arch, Debian/Ubuntu and Fedora. There are no Mac or Windows builds today.

Get started

Draw up your next job on your own computer.

Install the desktop app free today. Add Cadnat Plans when you want the set on your phone.

Linux download: coming soonSee plans