CAXCAD has more than 20 differently powful surface types，but we know that the features of the software can't meet the requirements of all users. Therefore, it is very iimportant to develop the user extended items. 

CAXCAD provides the extensions and the user can write their own surface types. 

The extension can be written in any language that support DLL, we also provide the VC++ examples.

You can find the standard DLL export function named "CAXExtendedSurface", there is a ray data format parameter CCAXDataRD，the user can find the detail in the header file surface.h

We can define the name, surface data and the ray data in surface.cpp

We can get the my_surface.dll file, put it in the directory DLL/Extended Surface

All the Extended Surface Dll can be found from the list

The extended surface used in the lens data manager.

We provide extended services to the users with customized surface types and integrated them into the software.