3d中获取对象包围盒-位置的常用方法

// 获取对象的包围盒getObjboundsById(objId){    var box = new THREE.Box3();    var bounds = new THREE.Box3();    var instanceTree = viewer.model.getData().instanceTree;    var fragList = viewer.model.getFragmentList();    box.makeEmpty();    bounds.makeEmpty();    instanceTree.enumNodeFragments(objId, function (fragId) {        fragList.getWorldBounds(fragId, box);        bounds.union(box)    }, true)    return bounds} // 获取中心位置getObjPosition(dbId){    var bound = vmethods.getObjboundsById(dbId);    var posx = (bound.max.x + bound.min.x) / 2;    var posy = (bound.max.y + bound.min.y) / 2;    var posz = (bound.max.z + bound.min.z) / 2;    var pos = {        x:posx,        y:posy,        z:posz    }    return pos;}