Free online STEP to GLTF converter

What the STEP format is

STEP, usually stored as .step or .stp, is an ISO 10303 exchange format for precise CAD geometry. It can contain B-rep solids, surfaces, assemblies, product structure, colors, and limited metadata, but it is not normally a rendering format.

Mechanical CAD programs such as SolidWorks, CATIA, Siemens NX, PTC Creo, Autodesk Inventor, Fusion, FreeCAD, and Onshape create or import STEP files. You encounter STEP when receiving engineering parts from suppliers, exchanging designs between CAD systems, or archiving manufacturing data.

What the GLTF format is

GLTF 2.0 stores polygon meshes, node hierarchies, materials, textures, cameras, and animations for efficient runtime delivery. A .gltf file normally references separate binary and image files; a .glb file packages the scene into one binary file and is usually easier to distribute.

GLTF is supported by WebGL viewers, Three.js, Babylon.js, Unity, Unreal Engine, Blender, many digital-twin platforms, and AR-capable applications. It loads faster than most general-purpose interchange formats because it is structured for rendering rather than parametric editing.

How to actually convert STEP to GLTF

Online conversion

For a straightforward conversion, use the free converter on 101convert.com: upload the .step or .stp file, select GLTF or GLB as the output, start the conversion, and download the result. Choose GLB when you need one portable file. Do not upload confidential designs unless the file-handling policy permits third-party processing.

Desktop conversion with FreeCAD and Blender

1. Open the STEP file in FreeCAD with File → Open.
2. Inspect the imported solids and hide construction geometry or unwanted parts in the model tree.
3. Select the objects to export and use File → Export. Choose OBJ when preserving separate object names or colors matters, or STL for a simpler single mesh.
4. If FreeCAD asks for tessellation settings, reduce the linear deviation and angular deviation for curved parts until the silhouette is sufficiently smooth. Smaller tolerances produce more polygons and larger files.
5. Open Blender and use File → Import → Wavefront (.obj) or File → Import → STL.
6. Check scale and orientation. STEP commonly uses millimeters, while Blender’s scene unit settings may not match the imported dimensions.
7. Use File → Export → glTF 2.0, select GLB for a single packaged file or GLTF Separate for separate geometry and texture files, then enable options such as Textures and Materials when required.

Some recent FreeCAD installations or extensions expose direct GLTF export. If File → Export offers GLTF or GLB, export the selected objects directly; otherwise, the FreeCAD-to-mesh-to-Blender workflow avoids relying on version-specific exporters.

Quality, compatibility, and limitations

STEP stores exact analytic and NURBS geometry, but GLTF stores triangulated meshes. The conversion therefore discards parametric features, sketches, constraints, manufacturing metadata, and editable CAD history; retain the original STEP file as the engineering master.

Tessellation controls the result: coarse settings create visible faceting and inaccurate silhouettes, while fine settings increase polygon count, memory use, and loading time. A curved mechanical part often needs finer angular deviation than a flat bracket.

Assembly structure may become a hierarchy of mesh nodes, but constraints and mating relationships do not transfer. Verify that every component is present and that nested transforms are correct.

Materials and colors may not survive the STEP-to-mesh stage, especially through STL. OBJ can preserve more appearance information, but Blender may still require material reassignment before GLTF export. GLTF supports PBR materials, so confirm roughness, metallic values, texture paths, normals, and transparency in the target viewer.

Check the exported file in the actual browser, engine, or viewer that will use it. Confirm units, axis orientation, face winding, normals, object names, texture references, and file size before distributing the model.