GLB viewer that keeps the whole scene in one file

They are the same format in two packagings. A .gltf is JSON that points at its geometry buffer and textures as separate files beside it; a .glb is that same JSON with the buffers and images embedded in one binary file. Everything a glTF can express, a GLB expresses identically — the difference is purely whether the payload travels with the description. That is why GLB is what you send to other people and glTF is what you keep in a repository where the .bin and the textures are versioned alongside it.

Draco is an optional glTF extension that compresses vertex data, and decoding it needs a WebAssembly decoder of roughly a megabyte. This page does not ship one, because it would be downloaded by every visitor to serve the minority of files that use it. Re-export without Draco, or run gltf-transform to decompress the file. The error names the extension so you know that is what happened, rather than leaving you with a blank viewport.

Yes when they are inside the file, which for GLB is the normal case — PNG and JPEG images embedded in the binary chunk are decoded and applied. The exception is KTX2 / Basis Universal textures, a compressed GPU format that needs a transcoder this page does not include; when the file uses those, the geometry loads and the error explains that the textures did not. The line under the viewport always states whether what you are looking at is textured, has vertex colours, or has no colour data at all.

Because animation is read past. A GLB can carry skins, joints and animation clips, and this page keeps the geometry and materials in the bind pose and ignores the rest — the measurements exist to answer dimensional questions, and a mesh in motion has no single bounding box to report. For checking a rig, load the file in Blender or a viewer built for playback; for checking whether it will fit on a plate or in a scene, the bind pose is the right frame.

Almost always because glTF splits a mesh wherever the material changes, and this page counts every triangle in every primitive across the whole scene. A modeller showing you one object with four materials reports its triangles once; the file contains four primitives, and the total is what gets drawn. The parts row appears under the panel whenever the scene holds more than one mesh, which is the quickest way to see that this is what happened.

Not on this page yet — conversion is a separate wave of tools on this site. What this page gives you meanwhile is the information that decides whether the conversion is even worth doing: a GLB with textures and vertex colours loses all of it in STL, and a GLB that is not watertight will not slice no matter which converter you use. The watertight row and the colour line are both visible before you commit to a pipeline.