Convert 3DM to glTF
Convert 3DM to glTF in your browser. The conversion runs on this page and the file never leaves your computer.
Result
Before you convert: what this keeps and what it destroys
Preserved
- The shape, to within the tessellation tolerance
- Overall dimensions and proportions
- Watertightness, where the input is watertight
- Colour
- Separate parts and their positions
Destroyed
- Exact curves and surfaces, replaced by triangles
- The feature tree and any parametric history
- A recorded unit: glTF stores none
Why people convert 3DM to glTF
The same route as 3DM to GLB, in the container you can read. Worth taking when you are wiring up a viewer and want to check what actually came across: the node names, the materials and the structure are all visible in the JSON.
The buffer is embedded as base64, so the result is a single file rather than the usual glTF scattering, at a cost of about a third in size.
Everything else matches the GLB route. Rhino's declared unit is converted into metres, object colours become base colours, and objects with no render mesh, meaning curves, points and annotations, are reported as skipped.
What you get
You get a plain-text glTF file you can open in an editor containing triangles. The reader tessellates supported surfaces or uses saved render meshes where required by the source format. Inspect curved faces at the intended output size. The triangle count depends on the model and the reader's meshing settings.
The output uses metres, as required by the glTF specification.
Carried across: supported base or vertex colour, the supported part structure.
The conversion runs in your browser. Your file stays on your computer and is not uploaded.
What to check afterwards
- 3DM declares its unit in the file. Check the output dimensions in the receiving application, especially when its import settings can override the unit.
- Curves become facets. 3DM stores exact surfaces, so a hole is a cylinder with a radius. glTF stores triangles, so that cylinder becomes a many-sided prism. Look at curved faces in the result at the size you intend to make the part.
If you need something this conversion cannot give you
If you need editable CAD geometry, don't convert at all. Open the 3DM file directly in FreeCAD, Fusion, Onshape or SolidWorks. Every mesh format destroys the exact surfaces, and no later conversion brings them back.
Going the other way
This site reads 3DM but does not write it. For the reverse conversion, use an application that can export 3DM.
How we know this conversion works
This pair was checked against 3 files from the test corpus on 2026-09-04. Each run parses its own output back in and compares the bounding box, the triangle count and, for closed solids, the volume against the input.
A pair that fails those checks doesn't get a page. That's why this site lists 120 conversions and not the several hundred a format-times-format grid would suggest.