Could you provide some more details on what you want to achieve exactly? BTW: Embree's subdivision surface implementation uses Gregory patches to approximate irregular subdiv patches after an initial adaptive subdivision phase.
Thank you for you reply,I read the source code about Embree,But in order to use the gregory patches I need to prepare some structure,like the half edge,But I don't find some API can help me to direct build the structure simple from a obj model.So my problem is can you give me some code about how to use gregory patch ACC method in Embree.
The problem is the entire bspline and gregory patch generation is done internally within the Embree core and not exposed to the user. The user only provides the input mesh and the tessellation factors. I guess you want to convert everything to gregory patches and then export the data into your application, right? In this case OpenSubdiv library might be an easier option for you.