Convert OBJ to STEP (Free)

Drop a .obj file, click Export, download the .step. The neutral CAD exchange format every mechanical package imports.

Also converts STL, GLB, PLY, USDZ, 3MF, WRL from the same file.

Runs in your browser. No upload, no signup, nothing to install.

Also from Innerscene: Circadian Lab, a free lighting calculator for room illuminance, melanopic EML, and glare.

Your OBJ file is read and converted on your own machine. It is never uploaded.

How to convert OBJ to STEP

1
Open your .obj file
Drag it onto the viewer above, or click "Open an OBJ File". Files up to 200 MB open directly; the parse runs in a worker so the page stays responsive.
2
Pick STEP AP214 in the Export menu
Click Export in the toolbar, then STEP (.step).
3
Download
The .step is written in the browser and saved straight to your downloads folder. No queue, no email, no watermark.

What survives the conversion

A file conversion is a translation, and formats do not carry the same things. Here is exactly what moves from OBJ into STEP, and what does not.

Geometry	Reduced	The triangles become a faceted B-rep: one planar face per triangle inside a closed shell. CAD reads it as real solid geometry with true units, but the faces stay faceted, they do not become NURBS surfaces.
Colors and materials	Dropped	STEP has no concept of color or materials, so the material colors in your OBJ file are not written. The geometry is unaffected.
Textures	Dropped	STEP does not carry texture images, so a textured model arrives in flat material colors.
Layers and structure	Dropped	STEP is a single flat body with no layers or named parts. Everything merges into one object. If you need the structure, export to GLB, OBJ, DXF instead.
Units and scale	Kept	STEP stores an explicit unit. OBJ does not, so the size is taken from how the viewer read the file. Check the scale once on import.

What the STEP writer emits: ISO 10303-21 AP214, each mesh written as a faceted B-rep: one planar face per triangle inside a closed shell, in millimeters under an explicit SI unit. Exact for polyhedral shapes, a faithful tessellation for curved ones.

The source: Wavefront OBJ (.obj)

Triangle and quad geometry, UVs and normals, with material colors from the companion .mtl file.

The target: STEP AP214 (.step)

The neutral CAD exchange format every mechanical package imports.

Opens in: SolidWorks, Fusion 360, Inventor, CATIA, NX, Creo, FreeCAD, Onshape.

Your file never leaves your computer

Both the OBJ parser and the STEP writer are JavaScript and WebAssembly running in your own browser tab. There is no upload step, no server-side conversion queue, and no copy of your file anywhere but your machine. That matters for drawings under NDA, for client work, and for anything you would not email to a stranger.

Frequently asked questions

▶Is this OBJ to STEP converter free?

Yes. No signup, no watermark, no per-file limit and no paid tier. Innerscene.

▶Is my OBJ file uploaded anywhere?

No. The file is read with the browser file API and converted in the same tab. Nothing is sent to a server unless you explicitly click Share, which is a separate, opt-in feature.

▶Will my colors and materials survive the STEP export?

STEP has no concept of color or materials, so the material colors in your OBJ file are not written. The geometry is unaffected.

▶Do layers and named parts carry into the STEP file?

STEP is a single flat body with no layers or named parts. Everything merges into one object. If you need the structure, export to GLB, OBJ, DXF instead.

▶Will the STEP open at the right size?

STEP stores an explicit unit. OBJ does not, so the size is taken from how the viewer read the file. Check the scale once on import.

▶How large an OBJ file can I convert?

Up to 200 MB, and the ceiling adapts to how much memory your device reports. The conversion runs on your own hardware, so a desktop with plenty of RAM will handle more than a phone.

▶Can I convert STEP back to OBJ?

Yes, the other direction works too. Bear in mind that anything the first conversion dropped is not restored by converting back. STEP → OBJ

▶Which browsers does it work in?

Chrome, Edge, Firefox and Safari, on Windows, macOS, Linux, iOS and Android. No plugin and no extension.