cesium：获取点击实体点的坐标位置

//获取的pick对象
var pick = viewer.scene.pick(event.position);  
// 获取点的经纬度
var cartographic = Cesium.Cartographic.fromCartesian(pick.primitive._actualPosition);
// 转换为数组，0经度，1纬度
var point=[cartographic.longitude / Math.PI * 180, cartographic.latitude / Math.PI * 180];
// 转换为Cartesian3
var destination=Cesium.Cartesian3.fromDegrees(point[0], point[1], 3000.0);