Convert ASC to glTF (Free)
Also converts STL, OBJ, GLB, PLY, 3MF, FBX 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 ASC to glTF
- 1
Open your .asc file
Drag it onto the viewer above, or click "Open an ASC File". Files up to 200 MB open directly; the parse runs in a worker so the page stays responsive.
- 2
Pick glTF separate (.gltf + .bin) in the Export menu
Click Export in the toolbar, then glTF (.gltf).
- 3
Download
The .gltf 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 ASC into glTF, and what does not.
| Geometry | Kept | Both formats store triangle meshes, so the shape transfers directly. |
|---|---|---|
| Colors and materials | Kept | glTF carries full PBR materials, which is at least what ASC stores, so the colors come across. |
| Units and scale | Kept | glTF stores an explicit unit, so the model opens at true size without rescaling. |
| Map coordinates | Reduced | glTF is written in local meters, centered on the data. OBJ, PLY, XYZ, DXF and DWG exports keep the map coordinates. |
What the glTF writer emits: The GLB export unpacked into its two parts: a JSON `.gltf` with `buffers[0]` pointing at an external `${base}.bin` (the source file’s own base name), zipped together.
The source: Esri ASCII Grid (DEM) (.asc, .grd)
An Esri ASCII Grid (ArcInfo ASCII raster) as a terrain mesh in metres, coloured by height, with no-data cells left as holes; a ZIP of tiles, such as a LiDAR download, opens as one mosaic placed by each tile’s corner.
The target: glTF separate (.gltf + .bin) (.gltf)
The same glTF scene as the GLB export, as the loose JSON and binary files some pipelines expect instead of one packed file.
Opens in: Blender, Unity, Unreal Engine, model-viewer, any glTF-separate pipeline.
Your file never leaves your computer
Both the ASC parser and the glTF 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.
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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 ASC to glTF converter free?
Yes. No signup, no watermark, no per-file limit and no paid tier. Innerscene.
▶Is my ASC 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 glTF export?
glTF carries full PBR materials, which is at least what ASC stores, so the colors come across.
▶Will the glTF open at the right size?
glTF stores an explicit unit, so the model opens at true size without rescaling.
▶How large an ASC 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 glTF back to ASC?
Not here. We read ASC and write glTF, 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 ASC to something else
Convert something else to glTF
Or start from the universal 3D viewer.