Text to STEP: generate a real STEP file from a text prompt
Type a part description and get back a real parametric STEP file: a watertight B-rep solid that opens in any CAD program, not a mesh.
Describe a part on the left, or tap an example, and a real STEP file shows up here.
What the tool does and what you get back
You describe a part in plain English. A model writes a parametric CadQuery script, that script executes on the OCCT geometry kernel, and you get a STEP file (.step / .stp) in return. The 3D preview and the geometry readout are measured from that generated STEP, so what you see is exactly what a CAD program or a shop would open.
The deliverable is a B-rep solid: exact surfaces, a closed watertight body, and real edges and faces you can select, measure, and dimension. Because the underlying model is parametric, the features it was built from (lengths, diameters, hole positions, fillet radii) carry through as named values you can change rather than a frozen lump of triangles.
Across prismatic, revolved, sheet-metal, and multi-hole multi-axis parts, the generator reliably produces a valid, dimensionally exact solid. It is a starting point you refine in your own CAD tool, not a finished production model, and it should be reviewed before anything gets cut.
STEP and B-rep, not STL or mesh, and why that matters
This is the line that separates an engineering tool from a render tool. A STEP file stores boundary representation geometry: the actual mathematical surfaces and the topology that joins them into a solid. An STL, OBJ, or GLB stores a mesh, a skin of flat triangles that approximates the shape and carries no notion of a hole, a fillet, or a flat datum face.
For a machinist or design engineer the difference is practical. A B-rep solid measures exactly, snaps to real edges and centers, and imports as an editable body. A mesh imports as one un-editable object, often non-watertight or zero-thickness, with arbitrary scale and a poly count tuned for looks rather than fabrication. You cannot reliably dimension it, fix a fit, or hand it to a CAM seat.
Most AI 3D generators output that mesh. A few text-to-CAD tools lock you into a proprietary format or list STEP export as a roadmap item. Text to STEP produces the STEP solid as the primary output, which is the format CNC, quoting, and inspection actually run on.
How it works: prompt to parametric CAD to STEP
The pipeline is deliberately boring where it needs to be trustworthy. A language model reads your prompt and emits a parametric CadQuery script, code that constructs the part from explicit operations: sketches, extrudes, revolves, bores, patterns, fillets, and chamfers.
That script runs on OCCT, the same open geometry kernel behind the FrankWorks estimator and behind tools like FreeCAD. OCCT builds the real B-rep solid, checks that it is closed and valid, and writes the STEP file. Nothing is traced over a mesh or surfaced from a point cloud. The geometry is constructed from first principles, which is why it is exact and editable.
Because the kernel is shared with the estimator, a generated STEP flows straight into the instant CNC cost estimate without a conversion step or a loss of fidelity.
Writing a prompt that lands
Fidelity tracks the spec. The generator will always return a valid solid, but how closely it matches your intent depends on how much you pin down. State the overall envelope in millimeters, the material, and each feature you care about: hole diameters and their pattern, wall and plate thickness, bore sizes, bend angles, fillet and chamfer radii.
Be explicit about quantities and positions. "Four M5 clearance holes on a 60 by 30 mm rectangular pattern" lands; "some mounting holes" leaves the placement to the model. In our own testing, giving the model the material distribution and key dimensions collapsed volume error by two to three orders of magnitude versus a vague prompt.
An under-specified prompt is not a failure. It still yields a valid, watertight solid, just a more generic one that you then refine by editing parameters in your CAD tool or by tightening the prompt and regenerating.
Honest limits, and from a prompt to a part made in Canada
Know the boundaries. Text to STEP is strong on prismatic, revolved, sheet-metal, and bolt-pattern geometry. It is not the tool for complex freeform surfacing, for reproducing an existing part to the millimeter, for tight GD&T and tolerance schemes, or for multi-part assemblies. Treat every output as a first model and review it before machining.
Where it earns its place is the cold start: turning a written spec into a real, measurable solid you can iterate on, instead of opening a blank sketch. From there the generated STEP drops straight into the instant CNC cost estimate, so you see what the part should cost to machine before you commit any further engineering.
When a concept becomes a real order, producing the part in Canada keeps it tariff-free under CUSMA and keeps proprietary or export-controlled designs onshore.
Frequently asked questions
- Can AI generate a STEP file?
- Yes. This tool writes a parametric CAD script from your prompt and runs it on the OCCT geometry kernel, which outputs a real STEP file: a watertight B-rep solid, not a mesh export. It opens in any CAD program and imports as editable geometry rather than a single faceted object.
- How do I generate a STEP file from a text prompt?
- Describe the part in plain English, including the overall size in millimeters, the material, and the features you care about such as hole diameters, patterns, thickness, bends, and fillets. The tool generates a parametric model, builds it into a solid on the OCCT kernel, and returns a STEP file you can download and open in your CAD tool.
- What is the difference between a STEP file and an STL file?
- A STEP file stores B-rep geometry: exact surfaces and the topology that joins them into a solid you can measure and edit. An STL stores a triangle mesh, an approximate skin with no holes, fillets, or datum faces as real features. STEP is what CNC quoting, CAM, and inspection run on; STL is mainly for 3D printing and rendering.
- Is AI-generated CAD editable and parametric?
- Yes. The output is built from explicit parametric operations, so dimensions like lengths, diameters, hole positions, and fillet radii carry through as named values. You can change them in your CAD tool, or tighten the prompt and regenerate. This is the difference from a mesh, which imports as one frozen object.
- Can I edit an AI-generated STEP file in SolidWorks, Fusion 360, or Onshape?
- Yes. STEP is the neutral CAD interchange format those programs read natively, and the output is a true solid body, so it imports as editable geometry. You can measure it, dimension off real edges and centers, modify features, and build on it the way you would any imported STEP part.
- Is text-to-CAD output manufacturable and CNC-ready?
- The output is a valid, dimensionally exact solid, which is the prerequisite for machining, and it flows straight into the FrankWorks instant CNC cost estimate. Treat it as a reviewed starting point rather than a finished production model: complex surfacing, tight tolerances, GD&T, and assemblies still need engineering work before you cut metal.
- Does the tool output a mesh or real CAD geometry?
- Real CAD geometry. It produces a B-rep STEP solid constructed on the OCCT kernel, not an STL, OBJ, or GLB mesh. That means exact surfaces, a closed watertight body, and selectable edges and faces, rather than a triangle approximation with arbitrary scale and no real features.
- How accurate is the generated geometry?
- Accuracy tracks the prompt. When you specify dimensions and features explicitly, the tool lands them precisely; in our testing, supplying the material distribution and key dimensions reduced volume error by two to three orders of magnitude versus a vague prompt. An under-specified prompt still returns a valid solid, just a more generic one you refine afterward.