Rotate a model to face camera

Hi,

How would I go about rotate a model to face the camera at all times?

Thanks for the help in advance.

Thanks,
Josh

Solved!

const direction = Cesium.Cartesian3.subtract(camPos, modelPos, new Cesium.Cartesian3())
      Cesium.Cartesian3.normalize(direction, direction)
      const rotationMatrix = Cesium.Transforms.rotationMatrixFromPositionVelocity(modelPos, direction)
      const rot90 = Cesium.Matrix3.fromRotationY(Cesium.Math.toRadians(90))
      Cesium.Matrix3.multiply(rotationMatrix, rot90, model.modelMatrix)