STL to STEP Converter — Real Faceted Solid Export
Convert one closed STL mesh into a real faceted STEP file, with edge topology checks, physical dimensions and a downloadable source copy.
Mesh to CAD
Choose your inputs, or load the working example to explore the result. Your files stay on this device.
Your inputs
Required fields are marked with an asterisk.
Your result
Review your output, then save it to your device.
Make the next step clear.
Your findings, assumptions and next steps will appear here after you run the check.
Mesh to CAD · https://cad.kitforma.com/ · KitForma
Runs locally in your browser
Download actual usable output
Explicit assumptions and supported inputs
Understand the evidence.
Focused guides explain the rules, the edge cases and the checks worth doing before you act.
What an STL to STEP conversion can preserve
Understand faceted solids before choosing an export.
Read the guide ↗Field guide / 02Prepare a watertight STL for a solid export
Why open edges and inconsistent faces stop the conversion.
Read the guide ↗Field guide / 03Check units and validate the exported STEP
Avoid a 25.4-fold scale error at the handoff.
Read the guide ↗Before you start
Is this genuine STEP?
Yes. The download is an ISO 10303-21 exchange file containing a FACETED_BREP with planar polygon faces and millimeter units.
Does it recover smooth CAD features?
No. It preserves triangular facets, not the original sketches, cylinders or feature history.
Why was my mesh refused?
The tool requires one consistently oriented, closed connected shell without duplicate or zero-area triangles. Its error lists the failing checks.
Are my designs uploaded?
No. Parsing, checks and exports run on your device.
Can it handle multiple parts?
Export each closed component separately. This version deliberately rejects disconnected shells rather than inventing assembly relationships.
Sources & assumptions
Formats, algorithms and supported features are documented below. Check the stated scope and inspect your output before using it.
- Convert3D: STL versus CAD solids ↗
Why changing a mesh format does not recover the original solid.
- STEP Part 21 exchange structure ↗
STEP schema and exchange reference.
Reviewed 2026-10-17. Read our methodology or report an issue.