No CAD installation needed. Open STEP/STP and compressed models (.stpz, .stepz, .zstep) instantly online and easily browse design details.
or click to browse, paste supported
STEP is a universal model exchange format in mechanical design, commonly used for parts and assemblies. This tool directly opens STEP files of various versions and natively supports compressed formats (.stpz, .stepz, .zstep), smoothly previewing high-precision surfaces and assembly structures. It supports rotation, zoom, and pan, making it easy to quickly inspect the model's appearance and assembly relationships. Files are processed locally only and are never uploaded. Need a printable mesh or exact sizes? Use STEP to STL, STL to STEP or 3D measure.
OffBoth open STEP files. The difference is what else you need to do.
| This online viewer | Desktop CAD (e.g. FreeCAD) | |
|---|---|---|
| Install needed | No | Yes |
| Runs on | Any modern browser, including phones and tablets | Windows, Mac and Linux computers |
| Price | Free | FreeCAD is free; other CAD programs are often paid |
| Edit the model | No | Yes |
| Measure | No | Yes |
Yes. After opening the assembly, you can inspect each part layer by layer by rotating and zooming. However, currently it does not support individually hiding or disassembling parts, but the overall structure is clearly visible.
Please make sure the file is complete and not corrupted. If it still doesn't work, try saving the file as AP214 or AP242 format using CAD software, then reopen it.
Yes. STP is just a short extension for STEP; the content is identical. This tool also supports compressed STEP files (.stpz, .stepz, .zstep), automatically decompressing and opening them directly.
STEP files can include colors, and this viewer shows them when they are in the file. Many CAD programs leave colors out when exporting STEP, so the model appears in a neutral grey. Turn on color export in your CAD program's STEP options and export again.
Yes. STEP is a neutral exchange standard, so files exported from SolidWorks, Fusion 360, Creo, CATIA, and other CAD tools open here directly.
The viewer turns the exact CAD surfaces into a display mesh on your own device. Big assemblies with many curved parts take longer, and a desktop computer handles them faster than a phone.