OSGB is a file format that originates from OpenSceneGraph.
It is supported as an exchange format by various 3D modeling tools.
The format describes a hierarchy of textured 3D models, similar to the OGC 3D Tiles format.
Each tile is stored in a separate .osgb file, which can use relative paths to reference
its children.
For more information, see http://www.openscenegraph.org.