Rendering of 3D model

CesiumJS
1

The look and feel of the model in Cesium is changing based on part of the day(like morning and night).
Kindly let us know if this can be suppressed.

2

There may be different ways to achieve that, depending on the question of which lighting conditions you want for your model. Maybe you just want to set a fixed time in the Cesium viewer, as in

const time = Cesium.JulianDate.fromIso8601('2013-06-20T11:00:00+00');
viewer.clock.startTime = time;
viewer.clock.currentTime = time;

?