OriginShape
Try Oscar

STL to STEP

Convert STL to STEP as real CAD, not a wrapped mesh.

Convert STL to STEP with AI: Oscar rebuilds the mesh as CAD features with named dimensions. The STEP file has true planes and cylinders that any CAD tool can edit.

Try OscarSend us a part
Oscar in the browser: a machined housing from an STL, colored by its distance from the rebuilt model, beside Oscar's list of why the large errors occur
The NIST housing sample. Oscar compares the model with the STL and says why the large errors occur.

How Oscar converts STL to STEP

A direct STL to STEP converter puts each triangle in the STEP file as a face. The file opens in CAD, but you cannot change a diameter. Oscar rebuilds the part as features first, so the STEP file has true planes and cylinders.

  1. 01

    Upload the STL

    Upload the STL file in your browser. Oscar also reads OBJ, PLY, and 3MF.

  2. 02

    Oscar rebuilds the features

    Oscar finds the axes, planes, and profiles. Then it builds sketches and features with named dimensions.

  3. 03

    You check the result

    Oscar flags each dimension that it cannot confirm from the mesh. You accept the value or change it.

  4. 04

    Export STEP

    Export a STEP file with true faces. It opens in SOLIDWORKS, Siemens NX, Autodesk Fusion, Onshape, and other CAD tools.

Worked example: a stepped shaft

Input
shaft_scan.stl · 8,000 points
Datum
One rotation axis
Features
Profile sketch · Revolve 1 · Taper 1
Dimensions
Ø24, Ø36, and Ø28 mm · 120 mm overall · 21.80° taper
For review
Shoulder position at z −35.00 mm: confirm
Output
shaft.step · a feature tree with named parameters
Example rebuild: a stepped shaft with shoulders and a linear taperØ24.00Ø36.00Ø28.0025.0050.0010.0035.00120.00shouldertaper 21.80°
OriginShape
TitleStepped shaft — example rebuild
Dwg no.ES-EX-001
ScaleNTS
Unitsmm
Sheet1 / 1
RevA
StatusExample
Illustrative example. Not a live scan conversion.

A converted mesh and a rebuilt part

Direct converterOscar
Faces in the STEP fileOne face for each triangleOne face for each real surface
Change a diameterNot possibleChange the parameter
Wear and scan noiseCopied into the fileFlagged for review
Feature treeNoneIn Oscar, and natively in FreeCAD

Common questions

On the blog: STEP or IGES? Which CAD file format to ask for

Why does my converted STEP file have thousands of faces?

A direct converter makes one STEP face for each triangle of the mesh. The file has the shape, but not the features. Oscar rebuilds the features, so a cylinder becomes one face.

Does the STEP file keep the feature tree?

No. STEP carries geometry only. Oscar keeps the feature tree and the named parameters in the app, and Oscar for FreeCAD saves them in the native FreeCAD file.

Can Oscar export IGES?

Not today. Oscar exports STEP and STL in your browser. Oscar for FreeCAD also exports 3MF and BREP. Most CAD tools import STEP.

Have a part without usable CAD?

Rebuild it with Oscar in your browser. If you do not have a scan, send us the part. We will plan the capture with you.

Try OscarSend us a part