We’re starting to refocus on 3D models using the upcoming glTF format from the COLLADA working group (which I am part of).
As Matt said, our implementation-in-progress is in the gltf branch. When you build that branch, run
Apps/CesiumViewer2/CesiumViewer.js has an example for loading a 3D model.
You can convert COLLADA models to glTF using an open-source converter that the COLLADA working group and the larger community is developing:
If you find issues in the converter, please submit them on their github page, not this forum. Anything you can do to make the converter solid is appreciated.
Currently, I’m working on adding glTF animations in Cesium. There is still a lot of loose-ends to tie up with our glTF implementation and the glTF spec, but I expect things to come together nicely in the next few months. During this time, I can only provide very limited support as I focus on development and spec work.