Another common service which should be provided by a TCAD framework for its applications is a functional interface for evaluating various physical models used by simulators. However, due to the tight dependence on the simulator implementation and the manifold concepts, defining a common interface and finding an appropriate model representation is not a trivial task. The VISTA material server (MAT) with its hierarchical material classification and its functional interface already provides a basis upon which a model server can be built and integrated into VISTA. As it is the case with other high-level libraries, the TAC will provide automatic binding of the interface functions to FORTRAN and LISP.
The hierarchical classification and encapsulation of models lets an object-oriented implementation be a tempting approach. The VISTA Object-Oriented Programming System (VOOPS) already provides a sound basis upon which object-oriented concepts can be realized within VISTA. The already existing class definitions for attributes and grids with their corresponding methods to read and write them to and from PIF, additional classes serving the purpose of model representation may easily derived from those GRS classes.