Cesium knowledge points (a): entity objects to add, get, delete

Add Entity

	var radarEntity = viewer.entities.add({
		id: 'radar',
		name: 'radar',
		position: Cesium.Cartesian3.fromDegrees(109.8, 19.997),
		rectangularSensor: new Cesium.RectangularSensorGraphics({
			radius: 2000,
			xHalfAngle: Cesium.Math.toRadians(90),
			yHalfAngle: Cesium.Math.toRadians(90),
			lineColor: Cesium.Color.GREEN,
			material: Cesium.Color.GREEN,
			showScanPlane: true,
			scanPlaneColor: Cesium.Color.WRITE,
			scanPlaneMode: 'horizontal',
			scanPlaneRate: 10
		})
	}) 

According to acquiring entity ID

var radar = viewer.entities.getById('radar')；

Deleting Entities

1, delete an entity based on solid objects

viewer.entities.remove(radarEntity);

2, ID to get entity objects according to delete entity

var radar = viewer.entities.getById('radar')；
viewer.entities.remove(radar );

3, delete all entity objects

viewer.entities.removeAll();