Modelling physics detectors in a computer aided design system for simulation purposes

Abstract The possibility of transferring physics detector modelsfrom computer aided designsystems into physics simulation packages like GEANT is receiving increasing attention. The problem of exporting detector models constructed in CAD systems into GEANT is well known. We discuss the problem and describe an application, called DDT, which allows one to design detector models in a CAD system and then transfer the models into GEANT for simulation purposes.