There are many situations in TCAD, especially when coupling different simulators, where interesting semantic problems occur on the data level. Among the most intriguing challenges are potential inconsistencies between the geometry of the simulation domain and one or more grids with attributes defined on them, altogether describing the current state of a wafer sub-domain.
These inconsistencies are inevitable, and are not a consequence of misbehaving applications or of an insufficient data representation or architectural concept. From the previous chapters it is evident that the simulators are specialized applications and that they must be allowed to focus on their specific task. It is reasonable and justified that they neglect all other issues. It is the duty of the framework to provide means for resolving those conflicts and inconsistencies.
Once these semantic gaps are bridged by the framework, simulators can work together constructively without having to care for potential grid-related conflicts they may create.
Many of the following problems would not arise if all simulators would be implemented newly, based on a common view and abstraction of wafer data, which is fairly unrealistic. But the simulators in use have been developed independently and are proven applications which must be accounted for and often must be accommodated within the TCAD system without any changes in the simulator.