I believe the problem is that the public glTF model converter on the website doesn’t yet create models that are compatible with the latest glTF spec which is used by Cesium 1.0. Once we release 1.0 tomorrow, we will update the converter and you should be able to convert to the new format.
If you are using the model converter on cesiumjs.org, Cesium 1.0, and eastNorthUpToFixedFrame, the orientation should be correct. If it isn’t, can you please post the model (COLLADA) and your example code?
Using Cesium web converter and eastNorthUpToFixedFrame the orientation
is wrong and the buildings are below terrain (an offset to the position
reveals their presence).
How was this COLLADA file generated? It does not open in Mac Preview (see the troubleshooting guide at the bottom of the tutorial). Regardless, the converter does not choke on it.
Looks like the up axis in the COLLADA file is wrong. Change it to:
Model orientation was changed in 1.0 to be consistent with the rest of Cesium, you should now use northEastDownToFixedFrame instead of eastNorthUpToFixedFrame.