modelMatrix

Scene/ModelExperimental/ModelExperimental.js 98
The 4x4 transformation matrix that transforms the model from model to world coordinates. When this is the identity matrix, the model is drawn in world coordinates, i.e., Earth's Cartesian WGS84 coordinates. Local reference frames can be used by providing a different transformation matrix, like that returned by Transforms.eastNorthUpToFixedFrame.
Default Value: Matrix4.IDENTITY
Example:
const origin = Cesium.Cartesian3.fromDegrees(-95.0, 40.0, 200000.0);
m.modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(origin);