Drop your 3D model here
The file opens in your browser and is never uploaded.
About the STEP format
STEP is the standard exchange format between CAD programs (ISO 10303): it describes exact surfaces, not triangles. It's mostly used for mechanical design and engineering (SolidWorks, Fusion 360, Onshape, FreeCAD, Inventor, CATIA), parts for manufacturing and suppliers, and it stores B-rep solids with exact surfaces (planes, cylinders, NURBS), assemblies, part names and colors.
How to open a STEP file
- 01
Drop the file
Drag your STEP file onto this page or tap to pick it. It opens in your browser: it is never uploaded to a server.
- 02
Look around the model
Rotate with the mouse or a finger, zoom with the wheel or a pinch, and double-click the model to center the view on that point.
- 03
Measure in millimeters
Click two points on the model to see the real distance between them. The whole model's dimensions show in the panel.
- 04
Convert it if you need to
If you need the model in another format, the converter turns your STEP into STL, OBJ, GLB and more, also inside your browser.
Frequently asked questions
Why does my STEP look faceted after converting it?
Because STEP describes mathematically exact surfaces and STL, OBJ or GLB only store triangles. When converting, OpenCascade, the same engine FreeCAD uses, covers every curve with triangles that stray from the real surface by less than 0.08% of the part's size: 0.08 mm on a 100 mm part, below what a 0.4 mm nozzle can reproduce.
Are the colors and the parts of an assembly kept?
Yes. Each body in the STEP arrives as its own mesh, with the color the CAD program gave it, if any. Converting to GLB or 3MF keeps them separate; STL merges everything into a single one-color mesh.
Is my CAD file uploaded to a server?
No. OpenCascade runs compiled to WebAssembly inside your browser: the part is read and triangulated on your computer. The first time, about 7 MB of the engine download, and then they stay cached.
Other viewers
Online STEP viewer
Drop your STEP file and explore it instantly: real-mm measurements, wireframe and screenshots. The file never leaves your computer.