There are 5 repositories under b3dm topic.
Renderer for 3D Tiles in Javascript using three.js
Convert OSGB,Shp,GDAL To Cesium 3DTiles
Tilers accepting various input formats (OBJ, 3DCity databases, GeoJson, IFC) and producing 3DTiles tilesets.
glTF to 3d Tiles Converter. Convert glTF model to Glb, b3dm or 3d tiles format.
gltf pipeline is a tool for gltf/glb/b3dm convert
3D tile content, glb and draco data viewer.
An 3dtiles/b3dm model local viewer/Explorer Tool
A bunch of handy script utilities relating to the .b3dm format.