# STL to STEP Assistant — Mesh Models to STEP Files

> Mesh Models to STEP Files (iPhone/iPad app by 维 艾.)

- Source: https://appshunter.io/ios/app/stl-to-step-assistant/id6769270457 (this page in markdown: same URL + `.md`)
- Developer: [维 艾](https://appshunter.io/developer/1771300149)
- Category: Developer Tools, Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.6 · 35 MB
- Languages: American English, French (France), German (Germany), Japanese, Chinese (Simplified, China)
- Released: 2026-05-17
- Data updated: 2026-08-25
- User reviews in markdown: https://appshunter.io/ios/app/stl-to-step-assistant/id6769270457/reviews.md

## What is STL to STEP Assistant?

STL to STEP Assistant is a focused local 3D model tool for converting mesh-based models into STEP files for CAD workflows.

Open STL, STLB, GLB, 3MF, USDZ, OBJ, 3DM, FBX, DAE, PLY, 3DS, AMF, DRC, KMZ, MPD, WRL, and other model files, preview them in a clean 3D scene, choose a conversion quality mode, then export and save the current main model as a STEP file. You can also load and view STEP and STP files to inspect conversion results.

Built for mesh-to-STEP work
- Convert STL, including binary STLB, to STEP
- Convert OBJ, GLB, GLTF, 3MF, 3DM (Rhino), FBX, DAE, PLY, USDZ, 3DS, AMF (additive manufacturing), DRC (Draco), KMZ (zipped 3D scene), MPD (multi-part LDraw), and WRL (VRML) model formats to STEP
- Load and view STEP files to inspect conversion results
- Export STEP with BRep reconstruction, useful for turning some engineering mesh models into easier-to-edit CAD surfaces
- Preview 3D models and BRep reconstruction results before export
- Export the current main model, not the whole scene or other objects
- Keep floor, lights, camera, and visual effects out of the STEP file
- Process files on device, so model data stays on your device
- Privacy focused, with no account, no login, no ads, no tracking, and no data collection

Choose STEP export geometry and quality as needed
- BRep: tries to convert suitable mesh models into easier-to-edit CAD surfaces, useful for some engineering parts and regular geometry
- Faceted Small: fast, lightweight STEP export for everyday use
- Faceted Balanced: balance detail and file size
- Faceted High: preserve more model detail
- Faceted Original: export as directly from the source mesh as possible

Understand the result before saving
- View source file information
- Review mesh, triangle, and vertex counts
- Check triangle reduction by quality mode
- Get a simple export risk hint
- See the final STEP file size after conversion

It is made for makers, engineers, designers, 3D printing users, CAD users, and anyone who needs to convert mesh models into STEP exchange files.

Pricing & Access
- Free: Open, preview, inspect models, load STEP files, and use Small STEP export.
- CAD Surface Export unlocks BRep STEP export for suitable models, helping produce easier-to-edit CAD surface results.
- In-App Purchase unlocks: Permanently unlock CAD Surface Export, Balanced, High, Original, and other STEP export capabilities. No subscription required.
- Payment is charged to your App Store account.
- Purchases can be managed through your App Store account settings.

Privacy & Purchase Terms
- Privacy Policy: https://h53d.github.io/s2s/policy.html
- Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Have questions or need support? Reach out to danjian42@gmail.com.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Unlock Faceted STEP Quality | $6.99 | one-time |
| Unlock CAD Surface Export | $9.99 | one-time |



## Version history (last 5 releases)

### 1.0.6 — 2026-08-24

- New Mesh Health check: after a model loads, it scans for open boundaries, non-manifold edges, duplicate triangles and similar issues; select a count to highlight those spots on the model
- New Export Prep: clean up the mesh before exporting and see what changed, with zero-area faces removed automatically by default
- Export results now report the Output Body type (Solid / Shell / Surface), flag 3D printing risk when the result is not a closed solid, and add a matching filename suffix
- Fixed BRep conversion failing on larger models, improved sphere detection for models far from the origin, and refined the preview and export panel messages

### 1.0.5 — 2026-07-28

- Improved the layout of the Recent Files list
- Improved the quality and stability of automatic BRep conversion, with better results for common planes, cylinders, cones, spheres, and fillets in mechanical models
- Improved BRep previews with clear, high-contrast colors for converted regions and regions retained as triangles, making conversion results easier to inspect
- Improved the STEP export workflow by reusing preview results for faster exports, and fixed extra surfaces appearing in some exported models

### 1.0.4 — 2026-06-18

- Added Faceted STEP preview: review Original, High, Balanced, and Small Size quality modes before export, with source file details and an in-scene preview of the converted model; you can also hide the original model to inspect the result alone
  - Improved conversion preview access: Faceted and BRep conversion previews remain free to use, and the daily free BRep export quota has been removed
  - Improved BRep surface reconstruction: better recognition of chamfers, fillets, cylinders, cones, frustums, and regular transition bands, reducing unnecessary faceted fallback areas in mechanical models
  - Improved BRep preview and export consistency: preview results can be reused during export, reopening preview no longer recomputes unnecessarily, and several preview display and region toggle issues have been fixed

### 1.0.3 — 2026-06-13

- Added BRep conversion preview: review analytic regions, coverage, fallback regions, and region details before export, with a visual preview of the conversion result in the scene
  - Improved Mesh-to-BRep results: enhanced recognition for planes, cylinders, cones, and spheres, making converted mechanical parts more structured and easier to edit
  - Improved scene controls: added a floor show/hide button and kept the scene still by default for more stable viewing and interaction
  - Improved recent file management: recent files now support per-item deletion and clear all, including cleanup of matching imported files stored by the app

### 1.0.2 — 2026-06-07

- Improved precision of Mesh-to-CAD BRep conversion: optimized recognition algorithms for cylindrical, spherical, planar, and crease features, delivering results that better match the original design
  - Optimized conversion for common mechanical part models, producing CAD models that are more structured and easier to edit
  - New free trial: convert Mesh to BRep and export STEP files several times per day — no purchase required

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All apps by 维 艾: https://appshunter.io/developer/1771300149

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-25.*