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STEP File Viewer Online
Open a .step or .stp CAD model and inspect it in 3D: rotate, zoom, see every part and the overall size. No CAD software needed.
Drag to rotate · scroll to zoom · right-drag to pan
Opened in your browser. The file is never uploaded to a server.
How to use the STEP File Viewer
Open the STEP file
Drop a .step or .stp file into the viewer or pick it from your computer. IGES (.igs) and BREP files open the same way.
Let the model load
The CAD geometry is turned into a 3D mesh on your device. Small parts appear in seconds, large assemblies can take up to a minute.
Inspect and save
Drag to rotate, scroll to zoom and right-drag to pan. Switch to wireframe, read the bounding-box size in millimetres or save a PNG of the view.
About the STEP File Viewer
STEP (ISO 10303, files ending in .step or .stp) is the format engineers use to send 3D models between CAD programs such as SolidWorks, Fusion 360, CATIA, Inventor, Creo and FreeCAD. Suppliers, machine shops and 3D-print services ask for it because it keeps the exact solid geometry, not just a triangle mesh. The catch is that you normally need CAD software to view STEP files, and installing a full CAD package to check one bracket is overkill.
This free STEP file viewer reads the file with OpenCascade, the open-source CAD kernel used by FreeCAD, compiled to run inside your browser. The model is triangulated on your own computer, so confidential parts and customer drawings are never uploaded anywhere. Colours stored in AP214 and AP242 files are kept, and each solid in an assembly is counted as a separate part.
Use it to check a model before you order parts, to confirm a supplier sent the right revision, or to view STEP files on a laptop, Chromebook or Mac where no CAD program is installed.
Frequently asked questions
How do I view STEP files without CAD software?
Open this page, drop the .step or .stp file onto the viewer and it appears in 3D after a few seconds. Nothing needs to be installed, and it works the same on Windows, macOS, Linux and ChromeOS.
Is this online STEP file viewer really free?
Yes. There is no account, no trial, no watermark and no limit on how many files you open.
Are my CAD files uploaded to a server?
No. The STEP file is read and converted to 3D inside your browser using a WebAssembly build of OpenCascade. The file never leaves your computer, which makes it safe for NDA and customer parts.
What is the difference between .step and .stp?
None. Both extensions are the same ISO 10303 format; some programs simply write the shorter .stp. The viewer opens both.
Can I measure or edit the model?
The viewer shows the overall dimensions of the model, the number of parts and triangles, and lets you inspect it from any angle. It does not edit geometry or measure between individual edges; for that you need a CAD program such as FreeCAD.
Why does a large STEP file take long to open?
STEP stores exact surfaces that have to be turned into triangles before they can be drawn. A big assembly with thousands of faces can take up to a minute on a slower computer. The page stays responsive because the work runs in a background thread.