cesiumobj转b3dm转换及加载
1、先下载安装node.js，再安oj23dtiles，在cmd中输⼊==>npm install -g obj23dtiles
2、新建⼀个json，设置obj的坐标等信息，经纬度采⽤弧度制，⾼程按地形⾼程输⼊，最多保留⼩数点后五位，内容如下 
{
"longitude":      -1.31968,
"latitude":      0.698874,
"transHeight":    1142.59807,
"region":        true,      // Using region bounding volume.
"box":            false,        // Using box bounding volume.
"sphere":        false        // Using sphere bounding volume.
//"minHeight": 0.0, // BoundingVolume minimum height in meters.
//"maxHeight": 40.0, // BoundingVolume maximum height in meters.
//"tileWidth": 200.0, // Tile horizontal(cross longitude) length in meters.
//"tileHeight": 200.0, // Tile virtical(cross latitude) length in meters.
//"geometricError": 200.0, // Tile geometric error in meters.
}
3、cd⾄程序执⾏的⽬录下，./代表当前⽬录，前⾯的路径为obj路径，后⾯的路径为json路径，⽣成tileset.json及b3dm⽂件  obj23dtiles -i ./east/east.obj --tileset -p ./east/eastoptions.json
4、将⽣成的⽂件导⼊⾄cesium⽬录下，然后加⼊以下代码对3dtile数据进⾏加载
var tileset = new Cesium.Cesium3DTileset({
url: "model/out8/tileset.json",
shadows:Cesium.ShadowMode.DISABLED,//去除阴影
});
//
viewer.scene.primitives.add(tileset);
3tiles
　5、模型偏移
var cartographic=Cesium.Cartographic.fromCartesian();
var old_cart=Cesium.Cartesian3.fromRadians(cartographic.longitude,cartographic.latitude,cartographic.height);
var new_cart=Cesium.Cartesian3.fromRadians(cartographic.longitude,cartographic.latitude,cartographic.height+100);
var translation=Cesium.Cartesian3.subtract(new_cart,old_cart,new Cesium.Cartesian3());
ps：程序也⽀持gltf、glb、i3dm
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