Generating CAD through the v1 API
You can generate real CAD parts programmatically through the v1 API, driving the same hardware engine the web app uses.
The endpoint
CAD generation is part of the CAD endpoint group under /api/v1. You call it with a project id and a plain-language prompt; you can also pass a parent design id to refine an existing part, and a color.
What it runs
The API drives the real HIIE CAD engine — a server-side build123d service on Railway that generates genuine B-rep geometry. Every generation runs a vision quality loop (generate, check the geometry, render snapshots, inspect, and refine) so the output is a real, structurally valid part rather than a degenerate shape.
What you get back
The generation produces three formats, archived as a versioned design in the project's Design folder:
- STEP — for CAD software like Fusion 360 or SolidWorks.
- STL — for 3D printing.
- GLB — a colored model for web viewing.
The API response omits the large base64 GLB to keep payloads small; instead you fetch the generated files by name through the Artifacts endpoint.
Scope and metering
CAD generation requires the build scope because it consumes resources. On the free tier, programmatic spend is held under a monthly cap. Each build123d generation meters a small flat rate (about 10 credits) with no monthly count cap; the premium Meshy text-to-3D path (2 free-plan generations per month, 75 credits each) is a separate web-app path, not part of this endpoint.
Refining a design
Pass a parent design id to iterate on a prior version; HIIE appends a new version (V2, V3, …) to the design lineage rather than starting fresh.