ReferenceProperty

Example:

var collection = new Cesium.EntityCollection();

// 创建一个实体并设置一个布告牌的比例。
var object1 = new Cesium.Entity({id:'object1'});
object1.billboard = new Cesium.BillboardGraphics();
object1.billboard.scale = new Cesium.ConstantProperty(2.0);
collection.add(object1);

// 创建第二个实体并引用第一个实体中的比例。
var object2 = new Cesium.Entity({id:'object2'});
object2.model = new Cesium.ModelGraphics();
object2.model.scale = new Cesium.ReferenceProperty(collection, 'object1', ['billboard', 'scale']);
collection.add(object2);

// 创建第三个实体，但是这次使用 fromString 帮助函数。
var object3 = new Cesium.Entity({id:'object3'});
object3.billboard = new Cesium.BillboardGraphics();
object3.billboard.scale = Cesium.ReferenceProperty.fromString(collection, 'object1#billboard.scale');
collection.add(object3);

//You can refer to an entity with a # or . in id and property names by escaping them.
// 您也可以使用如下方式来引用。
var object4 = new Cesium.Entity({id:'#object.4'});
object4.billboard = new Cesium.BillboardGraphics();
object4.billboard.scale = new Cesium.ConstantProperty(2.0);
collection.add(object4);

var object5 = new Cesium.Entity({id:'object5'});
object5.billboard = new Cesium.BillboardGraphics();
object5.billboard.scale = Cesium.ReferenceProperty.fromString(collection, '\\#object\\.4#billboard.scale');
collection.add(object5);