加载 3DTileset

    const tileset = await Cesium.Cesium3DTileset.fromUrl(config.url);

    let model = await viewer.scene.primitives.add(tileset, {
        disableDepthTestDistance: Number.POSITIVE_INFINITY,
    });

    viewer.scene.globe.depthTestAgainstTerrain = true;

    // 将3d tiles离地高度抬升20米
    let cartographic = Cesium.Cartographic.fromCartesian(tileset.boundingSphere.center);

    let surface = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0.0);

    let offset = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, -1.0);

    let translation = Cesium.Cartesian3.subtract(offset, surface, new Cesium.Cartesian3());

    tileset.modelMatrix = Cesium.Matrix4.fromTranslation(translation);

    ```