Should I use GLB or glTF?

GLB, unless a specific tool asks for glTF. GLB is one file with the textures inside it, so nothing can be lost in transit. glTF is useful when you want to edit the JSON by hand or serve the textures separately.

Do textures survive when I convert a GLB?

To OBJ, glTF, USDZ and 3MF, yes — you get a ZIP where the target needs one. To STL, PLY and OFF, no, because those formats have no concept of a texture. Every converter page here states which of the two it is before you upload anything.

Will animation survive?

Only to glTF, which is the same format. Every other target here is a static shape format, so an animated GLB arrives as the pose it was in. That pose is the rest pose, not necessarily the frame you were looking at.

Why is my GLB tiny in the slicer?

Because GLB is specified in metres and slicers read millimetres. A 20 cm model is 0.2 in the file. The converters here read the metre convention and write millimetres, so use the measurements shown beside the model to confirm before downloading.

GLB files, and how to convert them

GLB is glTF packed into a single binary file, and it is the best-designed format on this site. Geometry, materials, textures, animation and a scene graph all travel inside one file with nothing to lose on the way. When you can choose the format, this is usually the one to choose.

.glb · model/gltf-binary

GLB conversions that work today

Convert a GLB file into something else

Make a GLB file from something else

GLB guides

GLB and glTF are the same format

glTF is the format. It is JSON describing a scene, and it normally points at separate files: a .bin holding the raw geometry, and .png or .jpg files holding the textures. GLB is that same JSON with all of those files packed in behind it, as one binary blob.

So converting between them is repackaging, not conversion. Nothing is lost in either direction, and nothing is recalculated. Going to GLB packs the pieces in; going to glTF unpacks them, which is why that direction gives you a ZIP rather than a single file.

Use GLB unless something specifically wants glTF. One file is harder to break, and every viewer, engine and web page reads it.

What travels inside a GLB

Physically based materials: a base colour, how metallic the surface is, how rough it is, and normal maps for fine detail. This is the same material model used by every current game engine and renderer, which is why a GLB looks the same in Blender, in a browser and in Unreal.

A scene graph of named nodes, each with a position, rotation and scale. Skinning weights and animation channels, so a rigged and animated character survives as one file.

Units are fixed at metres by the specification. This is unusually helpful: a GLB does not have the unit ambiguity that STL and OBJ have, and a converter can convert correctly without asking you anything.

Converting a GLB for 3D printing

A printer needs an STL or a 3MF, and getting there means losing everything that makes a GLB good. The textures, the materials, the colours, the animation and the node structure all go, because neither target format has anywhere to put them.

What survives is the shape, and the shape is usually the point. What to watch is scale: GLB is in metres and slicers work in millimetres, so a model that looks right in a viewer will be a thousand times too small unless the conversion handles the units. Every GLB converter here does, and shows you the measured result before you download.

If the model has colour you want to keep, 3MF is the better target. It carries colour per triangle, and every current slicer reads it.

What GLB cannot store

Exact curved surfaces — GLB is triangles, like every other mesh format
A CAD feature history
Anything about how the model should be manufactured

GLB in detail

GLB compared, row by row
Property	GLB.glb
File contents	One binary file: a small header, the same JSON as glTF, then all the buffers and images.
Geometry	Triangles, with skinning weights and animation channels alongside them.
Units	Metres, fixed by the specification.
Colour and texture	Full physically based materials, with the texture images packed inside the file.
Separate objects	A scene graph of named nodes, each with its own position and rotation.
Published by	The Khronos Group, 2015, as the single-file packaging of glTF.
Written by	Blender, Sketchfab, Substance Painter, and every tool that ships models to the web.

Questions

Should I use GLB or glTF?: GLB, unless a specific tool asks for glTF. GLB is one file with the textures inside it, so nothing can be lost in transit. glTF is useful when you want to edit the JSON by hand or serve the textures separately.
Do textures survive when I convert a GLB?: To OBJ, glTF, USDZ and 3MF, yes — you get a ZIP where the target needs one. To STL, PLY and OFF, no, because those formats have no concept of a texture. Every converter page here states which of the two it is before you upload anything.
Will animation survive?: Only to glTF, which is the same format. Every other target here is a static shape format, so an animated GLB arrives as the pose it was in. That pose is the rest pose, not necessarily the frame you were looking at.
Why is my GLB tiny in the slicer?: Because GLB is specified in metres and slicers read millimetres. A 20 cm model is 0.2 in the file. The converters here read the metre convention and write millimetres, so use the measurements shown beside the model to confirm before downloading.