In the above sample, you can limit POIs based on a certain range. However , you can define other parameters as well and then simply define if a Drawable object is visible or not based on the value of the enabled property (more info here). Please note that setting
the 'opacity' property to '0' would also work. in that case the
triggers (`onEnterFieldOfVision` etc.) would continue to work, which
they would not when setting 'enabled' to 'false'.