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Open STEP, STP and IGES CAD files online

STEP, STP, IGES and IGS exchange precise CAD solids and surfaces between engineering systems. Tessellate supported models locally with OpenCascade WebAssembly and inspect them in interactive 3D.

Interactive viewer — This format is parsed and rendered in the browser.

Drop a STEP file to open it

or click to choose — everything stays on your device

Choose file

🔒 100% private — files never leave your browser

Sample files for STEP / IGES

Choose an extension below to open a ready-made sample in the viewer or download it for your own testing.

webtech360-machined-block.step

See how STEP / IGES works with this ready-made sample. Open it in the viewer or download the original STEP file for your own testing.

Download sample .STEP

webtech360-stp-sample.stp

See how STEP / IGES works with this ready-made sample. Open it in the viewer or download the original STP file for your own testing.

Download sample .STP

webtech360-iges-sample.iges

See how STEP / IGES works with this ready-made sample. Open it in the viewer or download the original IGES file for your own testing.

Download sample .IGES

webtech360-igs-sample.igs

See how STEP / IGES works with this ready-made sample. Open it in the viewer or download the original IGS file for your own testing.

Download sample .IGS

You can also edit STEP online — change the content with find & replace, then save it back. Nothing is uploaded. Or turn STEP into an image — snapshot the preview, add arrows or notes, and download a PNG.

What is a STEP file?

STEP, STP, IGES and IGS exchange precise CAD solids and surfaces between engineering systems. Tessellate supported models locally with OpenCascade WebAssembly and inspect them in interactive 3D. The .STEP extension identifies a STEP / IGES CAD model file, which is served with the application/step media type. You can open it here instantly — drop the file into the box above and it renders in your browser. Nothing is uploaded.

STEP is the preferred neutral exchange format for product geometry and assemblies, while IGES remains common for legacy surface and wireframe data. The optional OpenCascade engine reads the selected bytes in browser memory and creates display meshes from supported exact geometry, giving engineers a fast hand-off check without uploading confidential models.

Besides this free online viewer, you can open STEP / IGES files in desktop apps such as FreeCAD, SolidWorks, Fusion 360 — but here all you need is a web browser.

Quick facts

FormatSTEP / IGES — STEP / IGES CAD model
File extensions.step .stp .iges .igs
MIME typeapplication/step
DeveloperISO
Category3D, CAD & GIS
Also opens inFreeCAD, SolidWorks, Fusion 360

Common uses

What this browser preview can and cannot show

The display mesh is not a substitute for the original boundary representation. Product manufacturing information, GD&T, colours, layers, names, assembly relationships and attributes may be incomplete. Never take manufacturing or safety-critical measurements from the preview.

Tips for a reliable preview

How to open a STEP file online

  1. Click Choose file above, or drag your STEP file onto the box.
  2. The right viewer loads automatically and renders your file.
  3. Read, scroll or page through it. To open a different file, choose Open another file.

100% private — files never leave your browser.

Libraries used to render STEP in the browser

This viewer is built entirely with open-source JavaScript that runs in your browser:

Frequently asked questions

What is a .STEP file?

A .STEP file is a STEP / IGES CAD model, identified by the application/step media type. You can open and read it instantly in the viewer above without installing anything.

What programs open STEP files?

On the desktop, STEP files typically open in FreeCAD, SolidWorks, Fusion 360. Online, this page opens them in any modern browser — nothing to download.

Are STEP models uploaded for conversion?

No. Conversion to display triangles happens locally with a WebAssembly CAD engine. The engine downloads once when needed, but the model itself is not sent.

Can I edit a STEP file online?

Yes. Open your file, switch to Edit, change the text with built-in find & replace, then click Save. It all runs in your browser — nothing is uploaded.

How do I convert STEP to an image?

Use Snapshot to capture the STEP preview, optionally add arrows, text or highlights, then download it as a PNG image.

Is it safe to open my STEP file here?

Yes. The file is read and rendered entirely by JavaScript inside your own browser. It is never uploaded to a server, so nothing leaves your device.

Do I need to install anything to view a STEP file?

No. There is nothing to install and no account to create. Open the page, drop your file, and it displays instantly.

Does it work on my phone or iPad?

Yes. The viewer is fully responsive and works in modern mobile and tablet browsers such as Safari and Chrome.

Is there a file size limit?

There is no hard limit, but very large files depend on your device’s memory. Big files are processed in the background so the page stays responsive.

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