Who encountered such a problem
We’ve had other users report seeing black models: https://github.com/AnalyticalGraphicsInc/cesium/issues/3737
Do you have an example we could test with?
-Hannah
The issue at #3737 has just been closed and may resolve your issue. Look for the change in Cesium 1.45 on May 1, or get it now in the master branch on GitHub https://github.com/AnalyticalGraphicsInc/cesium.