3dtiles中的tileset文件学习

Question

3dtiles中文件有tileset和b3dm，网上的介绍都是翻译英文，没有示例说明，我现在手上有一个b3dm文件和tileset文件
其中，tileset的文件如下

{"asset":{"generatetool":"[e-mail]","version":"1.0"},"geometricError":79.3430061340332,"refine":"REPLACE","root":{"boundingVolume":{"box":[-121.749396860367,46.003837405704,-27.0957147525623,39.6715030670166,0,0,0,32.166482925415,0,0,0,18.142749786377]},"content":{"uri":"CEHUIYUANAZUO.b3dm"},"geometricError":2.48209381103516,"refine":"REPLACE","transform":[-0.889571355909471,-0.456796237665533,0.0,0.0,0.287848507473099,-0.560560192872803,0.776476340213864,0.0,-0.354691470845995,0.69073111079567,0.630146406074084,0.0,-2265300.46923007,4411477.68697441,3997600.82479962,1.0]}}

b3dm中的文件featureTableJson如下
{"BATCH_LENGTH":1,"RTC_CENTER":[-121.751370966202,46.0118349185213,-28.7213251041248]}

我想知道，到底是怎么通过tileset里的 transform矩阵和RTC_CENTER得到实际坐标的，矩阵计算过程即可，同时，boundingVolume里的中心点是怎么通过transform得到的