How to Generate a STEP File from Text

To generate a STEP file from text, describe the part precisely with real dimensions and standards, generate and review a preview, verify the result against your actual functional requirement, then export STEP for use in a real CAD package. The quality of the first draft depends almost entirely on how specific the description is — this is the single biggest lever you control in the whole process.

Step-by-step

1. Write the prompt with units, standards, and a clear reference geometry

"A bracket" gives a generation process almost nothing to work with; it has to guess thickness, hole placement, and overall proportions. "An L-shaped bracket, 60mm x 40mm x 5mm thick, with two M6 clearance holes 10mm from each end on the long side" gives it real constraints. Always include:

• Units — "about 20" is not engineering input; specify mm or inches explicitly.
• Standard part callouts where relevant — naming "M10" or "6205 bearing" lets the system pull exact catalog geometry instead of approximating a shape.
• Reference features — "10mm from the edge," "centered on the long axis" — gives the process a concrete anchor instead of an ambiguous "somewhere in the middle."

2. Generate and review the preview before committing further

Check overall proportions first — is this roughly the right size and shape before you get into detail review? A preview is a cheap sanity check; use it to catch a wildly wrong interpretation (wrong overall dimensions, a feature in the wrong location) before spending more time on the full generation cycle.

3. Accept the preview once the shape matches intent — but don't stop reviewing there

"Looks right" and "is right" are different bars. Once the overall shape matches what you described, move to checking the specific numbers that matter for function — see the review checklist below.

4. Download STEP and open it in your CAD tool for final verification

This is the step people skip most often, and it's the one that catches real problems: open the exported STEP file in SolidWorks, Fusion, or whatever you actually use, and check that a dimension you care about reads correctly, that fillets and features are clean, and that the file opens as a proper solid — not an open shell.

5. Escalate if the part is ambiguous or safety-critical

If your description was genuinely ambiguous (multiple reasonable interpretations existed) or the part is safety-critical or load-bearing, treat the generated STEP file as a draft for engineering review, not a final specification. See when to trust automation vs. ask an expert for where this line should be drawn.

A review checklist worth actually using

Before you treat a generated STEP file as final, check:

1. Does it open as a closed, valid solid in your CAD package — not an open shell or a set of disconnected surfaces?
2. Do the critical functional dimensions match your requirement — not just "looks about right" but the actual number you need (a bolt-pattern spacing, a bore diameter, a wall thickness)?
3. If the part mates with something else, did you specify (or check) an actual fit relationship — a hole and shaft that are each independently "10mm" is not the same as a toleranced fit pair. See tolerances in CAD: what AI tools usually get wrong.
4. For standard components, does the part match a real catalog part number, not an approximated shape that's merely close?

Common mistakes that produce a bad first draft

• Missing units. "About 20" forces a guess that may not match what you meant by 20 — 20mm and 20 inches are very different brackets.
• Vague fits. "A tight hole for the shaft" carries no actual diameter or tolerance strategy — specify the diameter and, ideally, the fit class you want (see our ISO thread guide for the fastener version of this, and our tolerances guide for the general case).
• Expecting organic, sculptural quality from mechanical-focused tools. A tool built around parametric mechanical features (extrusions, fillets, patterns, standard hardware) is not the right fit for free-form organic shapes — that's a different modeling problem with different tools.
• Treating the preview as the final check. A preview confirms the shape is roughly right; it doesn't confirm the dimensions are exactly right or that the part is manufacturable by your intended process — see DFM 101 for what still needs checking after the preview looks good.

The bottom line

Generating a STEP file from text is a workflow with real checkpoints, not a single black-box step. The description you write, the preview you review, and the final verification in a real CAD tool each catch a different category of problem — skipping any one of them is how a plausible- looking file ends up being the wrong part once it reaches a machine shop.

Related reading: What is a STEP file? · What is text-to-CAD and how does it work?