GLB Viewer and glTF Inspector
Open a 3D model and see what is actually inside it. Drop a GLB, glTF, FBX, OBJ, STL, PLY or Collada file below and you get the model on screen plus a full readout: the scene graph, every material and texture, how much video memory those textures will take, the draw call count, triangle and vertex counts, the skeleton, and any animations, which you can play. Nothing is uploaded, the file is read in your browser.
See what is actually in the file.
The scene graph, every material and texture, what those textures really cost in video memory, the draw calls, the skeleton and every clip. Draco, Meshopt and KTX2 files open too, and nothing is uploaded.
Exported by Khronos glTF Blender I/O v4.3
What the inspector tells you
Most model viewers show you the model. The useful question is usually why it's slow, why it looks wrong, or why it won't load at all, and that needs the numbers behind it.
Draw calls is the number that decides frame rate more often than triangle count does. Every mesh with its own material is a separate instruction to the GPU, and a model exported as two hundred separate objects will stutter on a phone even if the geometry is tiny. The counter in the status bar is the live per-frame figure from the renderer, not an estimate.
Texture VRAM is the one that surprises people. A 2048×2048 texture occupies about 22 MB in video memory once mipmaps are included, no matter how small the compressed PNG was. Four of those and you've spent most of what a mobile browser will hand you. The Textures tab lists each one with its real memory cost, largest first, which usually points straight at the problem.
The scene graph shows how the file is actually organised: whether your "one model" is forty nested nodes, whether the exporter left cameras and lights in the file, and where the skeleton starts. Bone chains stay collapsed until you open them, since a rigged character is hundreds of nodes.
Extensions tells you whether the file is compressed and how. KHR_draco_mesh_compression and EXT_meshopt_compression mean the geometry is packed, KHR_texture_basisu means the textures are KTX2. This viewer loads all three.
Why a file might not open elsewhere
Two cases account for most "the viewer just shows nothing" reports.
A .gltf file is not self-contained. It's a JSON file that points at a separate .bin for the geometry and separate image files for the textures. Opening the .gltf alone gives you an empty scene or an error. Drop the whole folder at once, select every file together, or zip the folder and drop the zip, and this tool wires the references back up. A .glb has all of that packed into one binary file, which is why it's the format to prefer for the web.
A Draco-compressed GLB needs a decoder that many viewers don't ship. If a file opens in Blender but not in a web viewer, this is usually why. The decoder is loaded here on demand, only when a file needs it.
What to do about what you find
If the numbers look bad, the fixes are separate tools, all of them running in the browser:
Run the file through the GLB optimizer to strip unused nodes, merge duplicate materials, compress the geometry with Draco or Meshopt, and resize oversized textures. That handles most of the draw call and download problems in one pass.
If texture memory is the issue, convert the textures to KTX2. They stay GPU-compressed in video memory rather than being expanded to raw pixels, which typically cuts that 22 MB figure to 3 or 6 MB.
If the model isn't a GLB yet, convert FBX or OBJ to GLB first.
If it's a character with no skeleton, the auto rigger adds one, and the animation library retargets 260 free motions onto it.
Common questions
How do I open a GLB file?
Drop it on the box above. GLB is a single binary file containing the mesh, materials and textures, so nothing else is needed. It opens in your browser with no install and no upload.
How do I open a .gltf file with textures?
Select the .gltf together with its .bin file and its texture images, or zip the whole folder and drop the zip. A .gltf references those files by relative path, so it can't render without them. This tool matches the references to the files you dropped.
Can I view an FBX file online?
Yes. Drop the .fbx here and it loads with its materials and animations. FBX is a binary format that also references textures externally, so include those files if the model came with them. If you need FBX as GLB for a web game, use the converter.
Does this upload my model?
No. Every file is read with the browser's own file APIs and rendered locally with WebGL. Nothing leaves the machine, which also means it works offline once the page is loaded.
Why does my model look black or shiny in the wrong way?
Almost always a PBR material with metalness set high and no environment to reflect. This viewer lights models with a filtered room environment for that reason, and the Light slider adjusts exposure. If a material still looks wrong, check the Materials tab for a metalness map you didn't expect.
Why is my triangle count higher than in Blender?
Blender counts faces, and quads are one face but two triangles. A GPU only draws triangles, so any quad-based model roughly doubles on export. The count here is what the GPU actually processes.
Can it show animations?
Yes. Any clips in the file are listed in the Animation tab with their duration and track count, and clicking one plays it. There's a speed control, and the Bones button overlays the skeleton so you can see what's driving the mesh.