Convert U3D to GLB (Free)
Also converts STL, OBJ, PLY, USDZ, 3MF, WRL from the same file.
Runs in your browser. No upload, no signup, nothing to install.
Also from Innerscene: Circadian Lab, a free lighting calculator for room illuminance, melanopic EML, and glare.
How to convert U3D to GLB
- 1
Open your .u3d file
Drag it onto the viewer above, or click "Open a U3D File". Files up to 200 MB open directly; the parse runs in a worker so the page stays responsive.
- 2
Pick glTF Binary in the Export menu
Click Export in the toolbar, then GLB (.glb).
- 3
Download
The .glb is written in the browser and saved straight to your downloads folder. No queue, no email, no watermark.
What survives the conversion
A file conversion is a translation, and formats do not carry the same things. Here is exactly what moves from U3D into GLB, and what does not.
| Geometry | Kept | Both formats store triangle meshes, so the shape transfers directly. |
|---|---|---|
| Colors and materials | Kept | GLB carries full PBR materials, which is at least what U3D stores, so the colors come across. |
| Layers and structure | Kept | Layers survive as real layers in the GLB file, so you can still isolate and toggle them. |
| Units and scale | Kept | GLB stores an explicit unit. U3D does not, so the size is taken from how the viewer read the file. Check the scale once on import. |
What the GLB writer emits: A single binary glTF with positions, normals, UVs and vertex colors, PBR materials, and each layer preserved as a named glTF node.
The source: U3D (Universal 3D) (.u3d)
The meshes of an ECMA-363 U3D file, or of the U3D model inside a 3D PDF, with each node placed, its material colours and the progressive-mesh detail resolved to the full level. A PDF with several 3D annotations opens the first model.
The target: glTF Binary (.glb)
The modern web and real-time 3-D format: one self-contained file with PBR materials.
Opens in: Blender, Unity, Unreal Engine, model-viewer, Windows 3D Viewer, AR apps.
Your file never leaves your computer
Both the U3D parser and the GLB writer are JavaScript and WebAssembly running in your own browser tab. There is no upload step, no server-side conversion queue, and no copy of your file anywhere but your machine. That matters for drawings under NDA, for client work, and for anything you would not email to a stranger.
Free to Use, No Signup
There are no accounts and no watermarks on this converter. If it saved you time, the one thing we ask is a mention: a post, a link from your blog or course page, or a reply to someone asking how to open a file.
Share it
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Hear about new formats
Occasional emails when the viewer learns a new format or gets a new tool.
Frequently asked questions
▶Is this U3D to GLB converter free?
Yes. No signup, no watermark, no per-file limit and no paid tier. Innerscene.
▶Is my U3D file uploaded anywhere?
No. The file is read with the browser file API and converted in the same tab. Nothing is sent to a server unless you explicitly click Share, which is a separate, opt-in feature.
▶Will my colors and materials survive the GLB export?
GLB carries full PBR materials, which is at least what U3D stores, so the colors come across.
▶Do layers and named parts carry into the GLB file?
Layers survive as real layers in the GLB file, so you can still isolate and toggle them.
▶Will the GLB open at the right size?
GLB stores an explicit unit. U3D does not, so the size is taken from how the viewer read the file. Check the scale once on import.
▶How large a U3D file can I convert?
Up to 200 MB, and the ceiling adapts to how much memory your device reports. The conversion runs on your own hardware, so a desktop with plenty of RAM will handle more than a phone.
▶Can I convert GLB back to U3D?
Not here. We read U3D and write GLB, but not the reverse. the universal 3D viewer
▶Which browsers does it work in?
Chrome, Edge, Firefox and Safari, on Windows, macOS, Linux, iOS and Android. No plugin and no extension.
Convert U3D to something else
Convert something else to GLB
Or start from the universal 3D viewer.