STEP to GLB converter
Drop your .step / .stp file — we convert it to .glb right in your browser. Files never leave your computer.
Why convert STEP to GLB?
GLB is what <model-viewer>, Three.js, Babylon.js, Unity, Unreal, and iOS Quick Look all read natively. If CAD needs to live on a website, a product page, or an AR preview, GLB is the destination — and converting once at the desk saves every visitor the cost of running a CAD kernel in their browser.
Who runs this conversion
Product marketing teams embedding 3D viewers on product pages, e-commerce adding AR previews, documentation teams publishing interactive technical drawings. Engineers publishing a spinnable part on their portfolio, too — this is the "Sketchfab-style" handoff.
Things that commonly go wrong
- STEP has no materials, so GLB arrives with a default metallic-roughness — expect to re-author PBR in Blender or glTF-Transform downstream.
- Large assemblies tessellate into multi-megabyte GLBs. Decimate or apply Draco compression if mobile matters.
- CAD coordinate axes (often Z-up) mismatch glTF Y-up — we handle the swap so previews are not sideways, but cameras in the target engine may need re-targeting.
Technical note for this tool
OCCT tessellation → Three.js Group → GLTFExporter in binary mode writes a single .glb. Embeds geometry plus a default metallic-roughness; textures are not fabricated (no source data).
STEP vs GLB— what's the difference?
ISO 10303 boundary-representation CAD format — the industry standard for exchanging precise, parametric solid models between engineering tools.
- Exact curved surfaces (NURBS / B-rep) — no tessellation loss
- Assembly hierarchy, part names and metadata preserved
- Supported by every major MCAD tool (SolidWorks, Inventor, Fusion, Creo, NX…)
- Open, vendor-neutral ISO standard
- Not directly consumable by 3D printers or game engines
- Files are larger and slower to open than mesh formats
- Requires a CAD kernel to read — no native browser support
Binary glTF — the JPEG of 3D. Self-contained, small, and loads natively on the web, in AR, and in every modern 3D engine.
- Everything (geometry, textures, materials, animations) packed into one file
- Tiny and fast — designed for streaming and web delivery
- Native support in Blender, Unity, Unreal, three.js, <model-viewer>, Android ARCore…
- PBR materials (metallic-roughness) render consistently everywhere
- Binary — not hand-editable
- Less common in traditional CAD pipelines
Deeper context on the formats
STEP — where it came from
Standardised as ISO 10303 in 1994 to replace the aging IGES format. Application Protocols AP203 (configuration-controlled design), AP214 (automotive), and AP242 (modern merge of both) define what data travels with the geometry — AP242 is the current default for new exports and is what most fabs expect in 2026.
- Assemblies exported with external references break when the .step file is moved without its companion files — always export as a single-file package (AP242 XML or monolithic .step).
- Kernel-to-kernel round-trips (e.g., Inventor → STEP → Fusion → STEP) can introduce tiny sliver faces and edge-tolerance drift; keep the original parametric file as the source of truth.
- PMI (product manufacturing information — GD&T, annotations) only rides along in AP242 — older AP203 exports strip it silently.
Real-world use: Mechanical suppliers quote from STEP, contract manufacturers program CNC toolpaths from STEP, and electronics vendors publish component 3D models as STEP on Digi-Key and Mouser. Any time a mechanical engineer hands off a design to a machine shop or an injection-mold vendor, it ships as STEP.
GLB — where it came from
glTF 2.0 was ratified by the Khronos Group in 2017 and quickly became the W3C-recommended format for web 3D. GLB is the "one-file-to-rule-them-all" binary packaging — geometry, textures, animations, and the scene graph all in a single .glb. Adoption was explosive because <model-viewer>, Android Scene Viewer, and every modern game engine landed support almost simultaneously.
- The PBR material model assumes linear-space textures — DCC tools that export gamma-baked colour maps will look washed-out in web viewers.
- Draco mesh compression bloats load time if the decoder is not preloaded; turn it off unless you actually need the bandwidth savings.
- Y-up vs Z-up: glTF is strictly right-handed Y-up. Blender, 3ds Max, and most CAD exports need an axis flip on import or the model lies on its side.
Real-world use: E-commerce product pages (IKEA, Amazon, Shopify 3D), Android AR Quick View, <model-viewer>-powered docs, NFT marketplaces, and real-time configurators. If a 3D asset has to render in a browser tab without plugins, the answer is GLB.
How to convert STEP to GLB
- 1Drag a .step or .stp file onto the drop zone. The CAD kernel runs in WebAssembly locally — nothing is uploaded.
- 2Inspect the tessellated model in the 3D preview. The Scene Tree on the left lets you toggle parts to check the hierarchy.
- 3Click Download .GLB to save a self-contained binary glTF — ready for three.js, <model-viewer>, Unity, Unreal, or Android ARCore.
FAQ
Why convert STEP to GLB?
STEP is unusable on the web — no browser speaks it natively. GLB is the web-native 3D format: tiny, self-contained, and loads in every modern engine. Converting once at the desk saves every visitor the CAD kernel cost.
Is my CAD uploaded to a server?
No. STEP is parsed by occt-import-js (WebAssembly OpenCascade) inside your browser, then re-exported as GLB by Three.js. Your data never leaves the machine.
Will the GLB keep the assembly hierarchy?
Part names and the basic hierarchy are preserved in the glTF scene graph. PMI, features, and parametric history are not — glTF has no representation for them.
Do curved surfaces stay smooth?
STEP's exact B-rep is tessellated into triangles during conversion — that's unavoidable when targeting a mesh format. We use a reasonable default deflection, which looks good on screen at normal viewing distances.
Can I use the GLB in <model-viewer> or an AR quick-look?
Yes for <model-viewer> (Google's web component — drop the file in and it renders). For iOS AR Quick Look you specifically need USDZ — the 3D viewer on this site can export USDZ directly too.