Question

现在有一个需求，就是一个多边形范围会发生变化（不规则），请问如何在变化前和变化后进行平滑过渡（动画效果），而不是在场景中简单移除掉变化前的,然后再加入变化后的。

                    if (_customPrimtiveCollection != null) {
                        window.CesiumViewer.scene.primitives.remove(_customPrimtiveCollection);
                        _customPrimtiveCollection = new window.Cesium.PrimitiveCollection;
                        window.CesiumViewer.scene.primitives.add(_customPrimtiveCollection);
                    }
                    window.CesiumViewer.entities.removeAll();

                    let instances = [];
                    for (var polygonKey of Object.keys(unions)) {
                        let poly = [];
                        for (var point of unions[polygonKey]) {
                            poly.push(point.x, point.y, point.z);
                        }

                        var instance = new Cesium.GeometryInstance({
                            geometry: new Cesium.PolygonGeometry({
                                polygonHierarchy: new Cesium.PolygonHierarchy(Cesium.Cartesian3.fromDegreesArrayHeights(poly)),
                                extrudedHeight: 0,
                                perPositionHeight: true
                            }),
                            id: polygonKey
                        });

                        instances.push(instance);
                    }

                    let myPrimitive = new Cesium.Primitive({
                        geometryInstances: instances,
                        appearance: appearance,
                        asynchronous: false
                    });
                    _customPrimtiveCollection.add(myPrimitive);

Answer 1

您好，可以设置entity的透明度，在变化的过程中同时不断地变化透明度