> For the complete documentation index, see [llms.txt](https://www.xrdev.app/mixed-reality-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.xrdev.app/mixed-reality-docs/webxr-lessons/3d-on-the-web/concepts/what-are-3d-model-loaders.md). # What are 3D model loaders? ### glTF (GL Transmission Format) Where possible, we recommend using glTF (GL Transmission Format). Both .GLB and .GLTF versions of the format are well supported. Because glTF is focused on runtime asset delivery, it is compact to transmit and fast to load. Features include meshes, materials, textures, skins, skeletons, morph targets, animations, lights, and cameras. Public-domain glTF files are available on sites like [Sketchfab](https://sketchfab.com/models?features=downloadable\&sort_by=-likeCount\&type=models), or various tools include glTF export: * [Blender](https://www.blender.org/) by the Blender Foundation * [Substance Painter](https://www.allegorithmic.com/products/substance-painter) by Allegorithmic * [Modo](https://www.foundry.com/products/modo) by Foundry * [Toolbag](https://www.marmoset.co/toolbag/) by Marmoset * [Houdini](https://www.sidefx.com/products/houdini/) by SideFX * [Cinema 4D](https://labs.maxon.net/?p=3360) by MAXON * [COLLADA2GLTF](https://github.com/KhronosGroup/COLLADA2GLTF) by the Khronos Group * [FBX2GLTF](https://github.com/facebookincubator/FBX2glTF) by Facebook * [OBJ2GLTF](https://github.com/AnalyticalGraphicsInc/obj2gltf) by Analytical Graphics Inc * …and [many more](http://github.khronos.org/glTF-Project-Explorer/) When glTF is not an option, popular formats such as FBX, OBJ, or COLLADA are also available and regularly maintained by many libraries. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://www.xrdev.app/mixed-reality-docs/webxr-lessons/3d-on-the-web/concepts/what-are-3d-model-loaders.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.