Kiln has always given you a printable mesh. Now it can give you real CAD too.
A print file is triangles: it prints fine, and that is all it does. Hand it to a machine shop and there is nothing to measure. Open it in a CAD program and there is nothing to edit, no faces, no holes, no dimensions.
As of Kiln 1.4.0, any design Kiln makes can also leave as a STEP file (the CAD format every engineering program and machine shop speaks): one clean solid with exact dimensions. Not a mesh wearing a CAD extension, the real thing, with surfaces a shop can measure and a CAD program can edit. It is free, like STL and 3MF.
What that changes
Say you describe a bracket to your AI agent and Kiln designs it. Until now that bracket lived and died as a print file. Now the same design leaves as CAD, which means:
- A machine shop can quote it. If the part outgrows your printer (you need it in aluminum, or a hundred of them), the file you send is the file they expect, with real dimensions they can measure and hold.
- An engineer can pick it up. Your design opens in the tools professionals already use, as editable geometry rather than a frozen shell.
- The dimensions are exact. A 40mm hole in the design is a 40mm circle in the file, not a 40-sided polygon that is almost 40mm.
Ask your AI agent to make something and include the CAD, and Kiln can hand you the STEP at make time, alongside the STL. Any design already in your library exports the same way.
And when it cannot be CAD, Kiln says so
Some things Kiln makes genuinely cannot be clean CAD: a photo turned into surface relief, text wrapped over a curved face. Faking a CAD file for those would produce something that falls apart the moment a shop measures it. So Kiln refuses, in plain language, and tells you why. A file you get is a file you can trust; a file that would lie is a file you do not get.
The round trip proves it: take the STEP Kiln exports, convert it back into a printable mesh, and you get the same part. Same dimensions, same details, down to the engraved lettering on a nameplate.
Bringing a CAD file in
Kiln has read STEP files since 1.3.0, and 1.4.0 makes the incoming side match the outgoing side’s honesty. A CAD file you bring in opens labelled as CAD, with the exact dimensions the file itself defines and the colours and part names it carries. You can ask print questions of it directly (“which way up should this print, will it warp, how much support?”) with no conversion step. And because reading CAD into a printable mesh is an approximation, Kiln Pro measures how close the conversion stayed and keeps that record with the part. See pricing.
Design in a conversation. Print it tonight. Send the same design to a shop next month. The file that leaves Kiln is the file the real world accepts, and that is the point.
More in the Kiln 1.4.0 release post, and the full detail is in the release notes. Kiln is an open-source MCP server: free at the core, AGPL-3.0, with paid tiers for deeper engineering features.