STEP Viewer — View STEP/STP CAD Files Online, Free
Open a .step or .stp CAD file and inspect the 3D geometry with orbit, pan, and zoom — no CAD software license required.
1. Choose or drop a file
2. View instantly
3. Download when done
What this viewer does
- Orbit, pan, and zoom camera controls
- Wireframe toggle
- Reset-view button
- Handles multi-solid assemblies in a single file
- Bounding-box dimensions for the loaded model
How it's rendered
OpenCascade (occt-import-js, WebAssembly). A WebAssembly build of the OpenCascade geometry kernel reads the STEP file's real B-rep geometry and tessellates it into a mesh for WebGL display — the same kernel many desktop CAD tools use internally.
Nothing about this file is ever sent to a server — open your browser's DevTools Network tab while using this viewer and you'll see no request carrying your file's contents.
100% Private
Files never leave your device. There is no server that ever receives your file's contents.
No Uploads
Every format is decoded and rendered locally via WebAssembly or JavaScript. Open your browser's Network tab and confirm nothing is sent.
No Storage
Nothing is written to a server or database. Memory clears the moment you close or reload the tab.
GDPR-friendly by design
There's no file data collection to comply with in the first place — no account, no tracking of file contents, no analytics on what you view.
STEP viewer — FAQ
What is a STEP file used for?
STEP (ISO 10303, often .step or .stp) is a neutral CAD interchange format used to move precise 3D geometry between different CAD programs — SolidWorks, Fusion 360, Inventor, CATIA, and others.
Do I need CAD software to open a STEP file?
No — this viewer reads the geometry directly in your browser and displays it in 3D, no CAD license needed.
Is this a full CAD viewer with exact geometry?
The underlying engine (OpenCascade, via WebAssembly) reads the file's real geometry, then tessellates it into a mesh for display — the same approach desktop CAD viewers use to draw curved surfaces on screen. Extremely large or complex assemblies may take longer to tessellate or, in rare cases, fail to render; see the on-page message if that happens.
Is my CAD file uploaded anywhere?
No, the entire STEP file is read and processed locally in your browser via WebAssembly.
Does .stp work the same as .step?
Yes, they're the same format with different file extensions — both open in this viewer.