Turn the model over
When Codex makes a part, it opens as a 3D model in the conversation. Rotate it and switch views to check every side before anything prints.
Use Kiln from Codex
Let Codex run your 3D printer.
Kiln gives Codex what it needs to design a part, check it will print, and run it on your own printer, from the Codex app, the terminal or your editor. You approve every print.
It opens right in the Codex app
Kiln shows its work as panels inside the conversation, so you see what Codex made before anything prints.
A check before it prints
Kiln checks the part will print and fits your printer, and flags what is likely to go wrong. With Kiln Pro, it also says exactly what to change.
Watch the print live
Ask how your print is going and a live monitor opens in the conversation, with its progress, temperatures and when it will finish.
Where a panel can’t show, Kiln hands back a link that opens the same 3D view in your browser. The live monitor needs Kiln running on the computer next to your printer.
An example session
Design a clip for 6 mm cables and print two on my printer.
The clip opens in 3D in the conversation
Done. It passed the print check. Want me to print two?
yes
It’s waiting for your OK.
You approve it
Printing two clips. I’ll keep an eye on it.
What Kiln adds
Codex can write the code. Kiln turns it into a part.
The same job both ways, from a description to a part on your printer.
| Step | Codex on its own | Codex with Kiln |
|---|---|---|
| Make it | Writes CAD code. Seeing the shape takes a CAD program on your computer. | Kiln builds the model and opens it in 3D right in the chat. |
| Check it | A problem shows up in the slicer, or partway through the print. | Kiln checks overhangs, thin walls, warping risk, and whether it fits your printer, before anything prints. |
| Change it | Ask again and get new code. Keeping track of which version was better is on you. | Ask for a change in the same chat, and Kiln keeps every try tied to what you first asked for. Pro makes it Git for 3D: what changed, drawn on the part, and a branch for the risky idea. |
| Slice it | Export the file, open your slicer, and pick the settings. | Kiln slices it in the slicer you already have: PrusaSlicer, OrcaSlicer, or Bambu Studio. |
| Print it | Send the file to your printer yourself. | Codex sends it to your printer, and it starts only after you say yes. |
| Watch it | Check on it in the printer’s own app. | Kiln watches every print it starts and stops it if a heater fails. A live monitor opens in the chat with the camera, progress, and pause and stop, and Codex checks the camera picture when you ask. |
| More printers | You run each one yourself. | Business runs several at once and picks the printer for each job. Free and Pro drive one at a time. |
The camera shows when your printer has one. A print can still fail, with Kiln or without it; Kiln catches what it can see before the print starts, and asks before it uses your plastic.
Set it up
All on the computer next to your printer.
Install Kiln on the computer by your printer
The quickest way is to paste the setup message from the install page into Codex, and it installs Kiln for you. Or follow the install guide yourself.
Connect it to Codex
The install guide ends with this command. It finds Codex and adds Kiln to it, for the Codex app, the terminal and the editor extension alike.
kiln install-mcpPoint it at your printer
Ask Codex to find your printer on your network, or tell it the brand and model. See the printers Kiln works with.
Ask for what you want
Describe a part or hand it a file. Kiln designs or checks it, gives you the 3D view, and waits for your OK before the printer starts.
Before it prints, Kiln asks you
A print uses real plastic on a real machine, so Codex can’t start one alone. Kiln shows you the model, then waits for a yes that only a person can give.
A tap on your phone
The print waits for you at kiln3d.com/monitor. Open it on your phone and tap Approve. Kiln has to be signed in on the computer it runs on.
A prompt where you work
When your setup can show Kiln’s approval prompt, you answer it right there.
Yes for a while
Say yes for the next two hours or the rest of today, and Kiln prints on that printer without asking again until then. You can end it early.
If neither is available, Kiln shows a four-digit code on the screen of the computer it runs on, and you type it in. Kiln never gives that code to your agent.
Questions
Can Codex 3D print?
Yes, with Kiln. Describe a part in Codex; Kiln designs it, checks it will print, and opens it as a 3D model right in the conversation. Kiln runs on the computer next to your printer, so Codex can send the print there, and you approve it. Tested in the Codex app, the terminal and the editor extension.
Can Codex make 3D models?
Yes. With Kiln connected, Codex turns a plain description into a real 3D model you can turn over, measure and change in the same chat, then print or download. No CAD skills needed.
What does Kiln add to Codex?
Codex can write the code for a 3D model. Kiln builds it, opens it in 3D right in the chat, checks it will print (overhangs, thin walls, warping, and whether it fits your printer), slices it in your own slicer, and sends it to your printer after you say yes.
Which model works best with Kiln in Codex?
The most capable one your plan offers. Today that’s GPT-6 Astra, or GPT-5.6 Sol. Kiln does the checking and the printing; the model does the thinking, so a stronger model means better designs and fewer retries.
How do I connect Codex to my 3D printer?
Install Kiln on the computer next to your printer and run kiln install-mcp; it adds itself to Codex. The setup steps on this page take a few minutes.
Does it work in the Codex app, the terminal and the editor extension?
Yes. All three read the same Codex setup, so connecting Kiln once covers them. Wherever a panel can’t show, Kiln hands back a link to the 3D view instead.
What about Codex on the web?
Codex on the web runs its tasks on OpenAI’s computers, not yours, so the Kiln you install doesn’t come along, and each task first needs a GitHub project to work in. To use Kiln in your browser, add it to ChatGPT instead: the 3D view opens right in the conversation. The ChatGPT page, linked below, shows how.
Do I need a 3D printer?
No. Codex can design and check parts with Kiln without one. You need a printer, or someone else’s, to make them.
Will it print without asking me?
No. Kiln shows you the model, then waits for your yes before every print. You can say yes for the next two hours or the rest of the day so it stops asking for a while, and you can turn on auto-print yourself. Auto-print is off unless you turn it on.
Which printers does it work with?
Bambu Lab, Creality, Prusa, Elegoo, and most Klipper and OctoPrint machines. The full list is on the supported printers page.
Is Kiln made by OpenAI?
No. Kiln is independent, open-source software you can use from Codex. It is not affiliated with or endorsed by OpenAI.
Set it up →Using ChatGPT? →Using Claude? →Using Cursor? →Using Gemini? →Using Grok? →Using OpenClaw? →
Kiln is independent, open-source software. It is not affiliated with or endorsed by OpenAI.