The standard format for 3D models is GLTF. The preferred version of this format is GLB (a binary GLTF file with all assets embedded inside).
We also support OBJ and FBX formats.
Other 3D formats can easily be used, as long as there exists a THREE.js loader for them.
Loaders are not included in the packages.
They are included inside each web-app, so that unnecessary ones need not be included.
Models are currently stored on the server, with a URL to the model in the document’s asset property.
GLTF models can use Draco compression, using this tool. This allows in some cases for up to 90% size reduction of geometry.