Convert STEP to OBJ
Free, in your browser, with nothing uploaded. Drop your .step file in and take the .obj away.
Drop your STEP file here
.step in, .obj out
Choose filesNothing is uploaded No account, no email No file size limit
How to convert STEP to OBJ
- 01
Add your .step file
Drag your STEP (ISO 10303) file onto the drop zone, or click it to browse. Nothing is uploaded: it is read where it already sits.
- 02
Check the preview
The model is parsed on your machine and drawn in the viewport, so a wrong axis or a missing texture shows up before you commit rather than downstream.
- 03
Save the .obj file
Press convert. The Wavefront OBJ file is written in the tab and lands in your downloads folder. No link, no expiry, no account.
What carries over, and what does not
A format conversion is a translation, and translations lose things. Here is what actually happens when an STEP file becomes an OBJ file.
| Data | STEP | OBJ | Survives |
|---|---|---|---|
| Geometry | Yes | Yes | Yes |
| Materials & colour | Yes | Yes | Yes |
| Texture maps | No | Yes | n/a |
| Animation & rigs | No | No | n/a |
| Scene hierarchy | Yes | Yes | Yes |
This is a comparatively lossless pairing: 3 of the five categories above are supported by both formats, so most of what is in your STEP file has somewhere to go in the OBJ file.
What our OBJ writer puts in the file
Geometry and texture coordinates, with a usemtl line naming the material on each mesh. No .mtl file is written to define those names, which is a limit of three’s OBJ exporter rather than of the format, so colours and texture images do not survive the trip. Convert to GLB or FBX if the materials matter.
About STEP (ISO 10303)
STEP is how serious CAD data moves between systems that share no code. It describes a part as a boundary representation, trimmed analytic and NURBS surfaces stitched into watertight solids, carrying tolerances and assembly structure rather than a mesh. Converting it means tessellating those surfaces into triangles, and that is a one-way trip: exact geometry is replaced by an approximation of it, and the parametric history is gone.
Commonly seen in: SolidWorks, CATIA, Fusion 360, Siemens NX, Creo, FreeCAD, Onshape. More on the STEP format page.
About Wavefront OBJ
OBJ is the closest thing 3D has to a lingua franca. It is a plain-text list of vertices, texture coordinates, normals and faces, first shipped by Wavefront Technologies in the 1980s and still readable by essentially every 3D application written since. Materials live in a separate .mtl sidecar file, which is why an OBJ often arrives untextured: the .mtl and the image files got left behind. OBJ stores no animation, no rig and no scene hierarchy beyond object and group names.
Commonly seen in: Blender, Maya, Cinema 4D, 3ds Max, ZBrush, MeshLab. More on the OBJ format page.
How the conversion works
When you drop a file in, the bytes are handed to a parser compiled to run in your browser. The STEP data is decoded into an in-memory scene graph of meshes, materials and transforms, which is what the preview is drawing. Pressing convert walks that scene graph back out through a OBJ writer and hands you the resulting bytes as a download.
The whole round trip is local. The page itself is static: it is delivered once and then does its work offline. That is why the privacy claim is checkable rather than a promise.
STEP to OBJ: common questions
Is my STEP file uploaded anywhere?
No. The file is read by code running inside this browser tab and never crosses the network. You can prove it by disconnecting from the internet before you convert, the page keeps working, or by watching the Network tab in your browser's developer tools while you drop a file in.
How large an STEP file can I convert?
There is no server-side limit because there is no server. The practical ceiling is your own machine's memory: a browser tab can usually handle models up to a few hundred megabytes. Very dense scans or scenes with millions of triangles will take a few seconds and a lot of RAM.
Why does my converted OBJ file look untextured?
Because this writer leaves them out. OBJ references an image by filename rather than storing it inside the file, so the images would have to travel separately and land where the file expects them, which is how a converted model arrives broken. Convert to GLB, FBX or USDZ instead if the textures need to stay with the model.
Does it cost anything?
No. There is no fee, no account, no watermark and no per-file limit. Since the conversion runs on your hardware rather than ours, serving this page costs about as much as serving a blog post.
Does it work on a Mac, on Windows or on a phone?
All of them. There is nothing to install: any browser with WebGL 2 will do, which covers current Chrome, Edge, Firefox and Safari on desktop, and Safari and Chrome on mobile. A phone has less memory than a laptop, so a very heavy scene may be the one thing it cannot finish.
Related conversions
Other things to do with the same file.
From STEP:
Other ways to get to OBJ:
Or do something else with it: