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About Open3D Viewer

Open3D Viewer is a free 3D file viewer app for Windows, Android, iOS, and the web. It opens the file formats people actually get sent — STL from 3D printers, GLB from web and AR pipelines, OBJ from modelers, STEP and IGES from CAD — without asking anyone to install a full modeling suite or make an account.

What it is, in one sentence

A dedicated 3D file viewer — you double-click a .stl / .glb / .step file and it opens, the same way images open in the Photos app.

Why it exists

Microsoft removed the Windows 3D Viewer app from the Microsoft Store on July 1, 2026. That app was the only mainstream, one-click way for a Windows user to see what was inside a .stl or .glb file. When Microsoft ended it, millions of files that were previously openable became "no app associated" errors.

Open3D Viewer is the free replacement. On Windows it registers the same file associations the old app had. On phones — where 3D printing hobbyists increasingly review files on the couch before slicing — there was never a good option. On the web, it's an "open a browser tab and drop a file in" viewer that works even on locked-down machines.

Not affiliated with the Open3D library from Intel Labs. Open3D Viewer is a consumer application. It is unrelated to the C++/Python Open3D library at open3d.org, which is a research/engineering library for 3D data processing. Different product, different team, no shared code. The name collision is unfortunate — the app was named for its function (opening 3D files), not with the library in mind.

How it's built

The rendering engine is three.js, wrapped in Flutter for the mobile + Windows shells and running natively on the web. That means the same behaviour, the same file support, and roughly the same UI across every platform. Files are read locally on the device — nothing is uploaded, no account is created, no telemetry beyond a crash log if the app crashes.

What it supports

Mesh formats: STL, GLB, GLTF, OBJ, PLY, 3MF, FBX, DAE, 3DS
CAD / engineering: STEP, STP, IGES, IGS, DXF
Point clouds: PLY from photogrammetry, LiDAR, Gaussian-splat exports

Who's behind it

Open3D Viewer is built and maintained by an independent developer, not a company. Contact goes to [email protected]. Feature requests and bug reports are read and, where reasonable, actioned quickly.

Pricing

The web viewer is free with light banner ads. The Windows app is free with no ads. The Android and iOS apps are free with a single banner ad. There are no subscriptions, no Pro tier, no "remove ads" upsell, no watermarks, and no plans to add any of these. The apps stay free because the total operating cost of the site is small and covered by the ads.

Get in touch

Support, feedback, feature requests, or corrections: [email protected]