//Set lighting
let light = SCNLight()
light.type = .ambient
node.light = light

// if light estimation is enabled, update the intensity
// of the model's lights and the environment map
if let lightEstimate = self.session.currentFrame?.lightEstimate {
    self.enableEnvironmentMapWithIntensity(lightEstimate.ambientIntensity / 1000.0)
} else {
    self.enableEnvironmentMapWithIntensity(6)
}

// Call environment Map
func enableEnvironmentMapWithIntensity(_ intensity: CGFloat) {

    if sceneView.scene.lightingEnvironment.contents == nil {
        if let environmentMap = UIImage(named: "Models.scnassets/sharedImages/environment_blur.exr") {
            sceneView.scene.lightingEnvironment.contents = environmentMap
        }
    }
    sceneView.scene.lightingEnvironment.intensity = intensity
}