I got a problem running collada2gltf to convert my own .dae file. So, to isolate the problem, I decided to try Cesium's own Cesium_Air3.DAE which is in Sandcastle's models to do the same thing. Here is what I did:
1. >collada2gltf.exe Cesium_air3.DAE
2. change the generated Cesium_air3.gltf to Cesium_air3.json.
Feed it to 3D models-Cesium's SandCastle. Then, rendering stopped with an error: Invalid indexDatatype.
What's wrong here. Please help. Thanks a lot.