What is the glTF file format?

glTF (GL Transmission Format) is an open, royalty-free industry standard developed by the Khronos Group for the efficient transmission and loading of 3D scenes. It is often referred to in the industry as the “JPEG for 3D” and serves as the highest-performing format for WebAR and interactive 3D product configurators in modern e-commerce.

Does glTF support photorealistic materials?

Yes. By default, the glTF format uses the Physically Based Rendering (PBR) workflow. This ensures that complex materials such as brushed metal, open-pore wood, or fine fabrics are rendered with absolute physical accuracy and photorealism under various real-time lighting conditions—a critical factor for premium brands.

Why is glTF important for e-commerce?

Thanks to advanced compression methods (such as Draco or Meshopt compression), glTF drastically reduces the file size of high-resolution 3D models. This enables lightning-fast load times directly in the browser. This performance prevents shopping cart abandonment, increases user dwell time, and significantly boosts the conversion rate through interactive product experiences.

How does glTF differ from Apple's USDZ?

While USDZ is a proprietary high-end format designed specifically for Apple’s iOS ecosystem (AR Quick Look, visionOS), glTF/GLB serves as the open, cross-platform standard for nearly all web browsers and Android systems. A professional 3D visualization studio always implements a dual workflow for e-commerce clients to ensure optimal support for all end devices.

What is glTF - The 3D file format for web, AR & e-commerce

Q: What is the difference between glTF and GLB?

glTF is based on an open JSON structure that often references external textures and binary data (.bin). GLB, on the other hand, is the compressed, purely binary version of glTF, in which all data (geometry, PBR textures, animations) is bundled into a single file. GLB is the absolute best practice for seamless use in CMS systems and online stores.

Glossary

What is glTF?

Martin Keller

•

Last updated:

May 11, 2026

In this glossary article:

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Glossary

What is glTF?

Martin Keller

•

Last updated:

May 11, 2026

Definition of glTF / GLB

glTF (“GL Transmission Format”) is an open file format maintained by the Khronos Group that stores 3D geometry, PBR materials, and animations in lightweight JSON and binary chunks (GLB). It is often referred to as the “JPEG of 3D” because it delivers render-ready assets with minimal overhead in the browser—see our WebGL showcase —in Unreal Pixel Streaming (demo on the 3D Render Studio page), or in AR Quick-Look (examples under Augmented Reality 3D).

Why is glTF beneficial for brands?

Advantage	Effect for Home & Living brands
File size	~4–10 times smaller than FBX; loads faster in the 3D configurator.
Complete PBR	Albedo, Normal, Roughness, and Metalness in one package → a consistent look.
Web-Native	Direct loading in WebGL, Three.js & Shopify viewer without plug-ins.
AR-Ready	Convertible to USDZ / Reality Composer for AR Quick Look.
Open Standard	No licensing fees, extensive tool support (Blender, Substance, Sketchfab).

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From Technical Term to Visual Experience

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Technical Fundamentals

JSON + BIN – Text descriptor plus binary buffer for geometry.
PBR Schema – Metal/Rauh Workflow as in Unreal/Unity.
Draco Compression – optionally reduces vertex data by ~60%.
KHR_materials_variants – a glTF extension that represents variants without duplicating assets (perfect for 3D configurators).

The technical article “glTF: Behind the Scenes of 3D Magic” —where you’ll find background information on file structure, extensions, and performance tweaks.

Real-World Comparison: glTF vs. FBX vs. USDZ

Criterion	glTF / GLB	FBX	USDZ
Rendering	WebGL, Unreal, Unity	DCC, Offline Rendering	Apple AR Quick Look
File size	small	large	medium
License	Open Source	Proprietary (Autodesk)	Apple Open
PBR-Ready	✅ KHR Standard	❌ Shader-dependent	✅ Pigment Properties
Best Use	E-Com Viewer, Config	DCC Exchange	iOS AR Preview

Workflow: Exporting glTF in 6 Steps

CAD Cleanup → triangulation, hard edges, separate meshes for each variant.
UV mapping → 0-1 space; texel density as defined in theUV mapping glossary.
PBR Textures → Albedo, Normal, Roughness, Metalness (→ Roughness Map).
LOD Stacks → Automatic Reduction (30%, 10%).
Activate Export →.glb (Binary) with Draco compression.
QA → load in the glTF Viewer & in our 3D product configurator.

Example of glTF on the Web

Quick Tips

Vermeide 32-bit-PNG: < 2 k Texturen als JPEG + sRGB; Metallic/Roughness als 8-bit PNG.
Use KHR_texture_transform for scaled tile maps instead of UV overlaps.
With > 50 material variants → KHR_materials_variants saves setup time in the configurator.

FAQ - glTF / GLB File Format

What is the difference between glTF and GLB?

glTF is a JSON-Plus binary structure spread across multiple files, while GLB packs everything into a single binary file—ideal for CMS uploads.

What is the maximum size allowed for a GLB in a web viewer?

Richtwert: < 15 MB inkl. LODs; für Mobile Pixel-Streaming unter 8 MB.

Does Shopify support glTF?

Yes, via the Shopify Model Viewer. Example: Bosch Rexroth used a Unity → glTF → Shopify setup. (See the Unity case study.)

Can I convert FBX to glTF?

Yes—Blender, FBX2glTF-CLI, or KennyTools; check the materials, since Spec-Gloss is converted to Metal-Rough (Rough = 1-Gloss).

How do I integrate glTF into a 3D virtual showroom?

Our 3D Virtual Showroom glossary page illustrates the workflow using Three.js Loader and light probes.

How do I choose the right texture resolution for glTF models?

Guideline: 1–2 k for pure web viewers, 1 k for AR Quick Look, and up to 4 k for pixel streaming—depending on viewing distance and target device. For additional guidelines, see the official glTF spec repository under “K - Images.”

Does glTF support transparent materials such as glass or acrylic?

Yes—using the KHR_materials_transmission (refractive glass) and KHR_materials_alphaMode (for simple opacity) extensions.

Can I import physically based textures in JPEG XL or AVIF format?

glTF 2.0 accepts all MIME types; most viewers support PNG / JPEG. A fallback is currently required for AVIF & JXL (see compatibility matrix in the glTF GitHub repo under "Texture Formats").

How can I quickly test the basic compatibility of my glTF file in a browser?

Using Don McCurdy's free glTF viewer or our in-house viewer—just drag and drop, and shader errors are highlighted in red.

Can animation bones and morph targets be used at the same time?

Yes; glTF supports both types, but older web viewers do not support Morph + Skeletal at the same time—check beforehand.

Which compression workflow is better—Draco or MeshOpt?

Draco offers a higher compression ratio (~60%), but requires JavaScript decoding; MeshOpt is faster and saves ~50%. You can find a practical comparison on Keysoft (under the “Compression” section).

How do I integrate variant swaps (color, fabrics) without duplicates?

Use KHR_materials_variants: one mesh, multiple material slots, variant JSON—ideal for 3D configurators.

Can I save shader nodes (e.g., clear coat) directly in glTF?

Only through extensions like KHR_materials_clearcoat. Proprietary shader graphs must be baked into PBR maps beforehand.

What is the maximum polygon count for smooth web performance?

Up to ~100,000 triangles per asset is common in WebGL-2; for larger numbers, use LOD levels or instancing.

How do I migrate an existing FBX pipeline to glTF without losing any materials?

FBX → Blender Import → “Spec/Gloss → Metal/Rough” Converter → glTF Export with tested shader presets. You can find step-by-step instructions in the Blender glTF documentation and in the corresponding glTF-Blender-IO GitHub repository.