glTF viewer online
Open glTF files instantly — measure in mm, cut a section, spot overhangs and check if the model is ready to print. Nothing is uploaded.
What is a glTF file?
glTF was developed by the Khronos Group, the body behind OpenGL and Vulkan, and version 2.0 was released in 2017 and later adopted as ISO/IEC 12113. The design goal was a lean transmission format that engines can load without heavy processing. In its text form, a .gltf file is JSON that lists scenes, nodes, meshes, materials, animations and accessors, and it points to external .bin buffers and image files, though buffers can also be embedded as base64 data. The same content packed into one file is called GLB. Because the JSON is readable, glTF is popular for tooling, pipelines and debugging, and for projects that want to diff or hand-edit assets. It uses metres, a right-handed coordinate system and +Y up, and its physically based materials are supported by most web and game engines.
What a glTF file can store
A glTF file stores a node tree with transforms, meshes made of triangle, line or point primitives, vertex attributes such as normals, tangents, UVs and colours, and PBR metallic-roughness materials. Images are referenced by URI or embedded as data URIs. It can describe skeletons, morph targets, keyframe animations, cameras and lights through extensions. All distances are in metres. Unlike OBJ, textures and materials are part of the same specification, so appearance is standardised rather than guessed.
Apps that open glTF
Blender, Three.js, Babylon.js, Unity, Unreal Engine, Godot, Cesium, Maya, 3ds Max, Sketchfab.
Strengths
- Readable JSON that is easy to validate and script
- Open ISO-registered standard maintained by Khronos
- Well-defined PBR materials and animations
- Metres and +Y up are fixed by the spec
Limits
- Multi-file layout makes sharing fragile; one missing .bin breaks the model
- Base64-embedded buffers are about a third larger
- Not read by most slicers
- No concept of print tolerances, supports or watertight solids
glTF and 3D printing
glTF is a display format, so a slicer will not open it. Convert it to STL or 3MF first. As with GLB, the main traps are metres versus millimetres and the Y-up axis. A character exported from a game pipeline can also contain separate shells for eyes, clothing and hair that overlap; slicers see overlapping volumes and may print them unevenly. MeshShift reads glTF in the browser, shows dimensions, applies the ×1000 metre-to-millimetre scale by default, and rotates the model upright. The print check rebuilds a single closed solid when you need one. When writing glTF, MeshShift embeds the buffers, so the output is a single self-contained file.
Frequently asked questions
How do I open a glTF file without installing software?
Drop the glTF file on this page. It opens in your browser with studio lighting and real dimensions; nothing is uploaded. You can rotate, zoom, measure between two points, cut through the model and check whether it is watertight for printing.
Should I use glTF or GLB?
Choose GLB when you want to share, upload or ship one file with textures inside. Choose glTF when you need to read or edit the JSON, keep textures separate, or let a version control system show changes. Both are the same standard and convert losslessly.
Why does my glTF show missing textures?
A .gltf usually references external image and .bin files by relative path. If you moved the file without them, or a web server blocks them, the viewer cannot load the data. Keep the folder together, or repack everything as a single GLB.
Can MeshShift read and write glTF?
Yes. MeshShift reads glTF and writes glTF with embedded data, so the result is one file. It runs in your browser without uploading anything, converts glTF to STL or 3MF with automatic metre-to-millimetre scaling, and can also save GLB.