Convert glTF to STEP through STL
There is no direct upload for glTF to STEP. Convert the glTF file to STL in your browser, then upload the STL to STL to STEP, which rebuilds it as a faceted solid.
Before you convert: what this keeps and what it destroys
Preserved
- The shape, as planar faces built from the triangles
- Overall dimensions and proportions
- Watertightness, where the input is watertight
- The unit, recorded in the file
- Supported base or vertex colours
- Separate parts and their positions
Destroyed
- Cones, spheres, tori and NURBS, rebuilt as planar facets
- Animation, rigs, cameras and lights, if the file has them
- Texture images and texture coordinates, if present
↺ the reverse: STEP → glTF · about .gltf · about .step · just view it instead
Why people convert glTF to STEP
Turning a web asset into something a CAD or CAM package will accept, which usually means somebody has been sent a glTF of a part and asked to quote or make it.
The output is a faceted B-rep: planar faces built from the triangles, shared edges, and a closed shell where the input was closed. Treat it as reference geometry. There is no exact surface anywhere in a glTF to recover, so there are no cylinders, no NURBS and no feature tree in the result.
Two practical checks. Coordinates are multiplied by 1000 from metres into millimetres, so confirm the size looks right. And rendering assets are often open shells, which limits how solid the reconstruction can be.
What you get
You get a plain-text STEP file you can open in an editor containing a boundary representation: planar faces, shared edges and, where the input was closed, a closed shell that CAD software will treat as a solid. Triangles that lay in the same plane are merged into single faces, so a flat side that arrived as two hundred triangles leaves as one face.
This conversion carries across the unit the file records, supported base or vertex colour and the supported part structure.
This page does not upload anything. The server converts STL to STEP only, and nothing else on this site leaves your computer.
What to check afterwards
- glTF and GLB use metres by specification. This converter interprets the source coordinates that way. If the model was authored at a different scale, confirm a known dimension before using the output.
- The numbers change. STEP is read in millimetres and glTF in metres, so every coordinate is rescaled. The result is the same physical size, but the numbers in the file are different numbers.
- This is a reconstruction, not a recovery. Coplanar triangles are merged into planar faces and the result is a real solid, but cones, spheres, tori and NURBS surfaces are not recovered and there is no feature tree. Use it as reference geometry.
If you need something this conversion cannot give you
If you need a parametric model, use the original CAD file or remodel the part using this output as reference. Surface fitting can create new geometry, but a mesh does not contain the original sketches or feature history.
Going the other way
Convert STEP back to glTF is the reverse page. It is not the inverse of this one: reconstructing a solid from triangles produces faceted geometry, and tessellating it again would not return you to where you started.
How we know this conversion works
This pair was checked against 1 file from the test corpus on 2026-09-24. 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.