Absorbing CAD system geometries into GEANT

The simulation community has for many years discussed the possibility of direct conversion of geometrical detector models from computer- aided design and engineering systems (CAD systems) to the simulation packages (which we shall assume means GEANT). This would allow fast and simultaneous optimization of the physics performance and structural integrity of detector designs. The benefit that this would offer is the avoidance of such problems as the late discovery of the rather thick cryostats in the D-Zero detector. Recent progress in the absorption of CAD geometries into GEANT models is reviewed, including descriptions of the additions to the I-DEAS solid modeller package developed for the EMPACT SSC proposal, the COGENT CAD-to-GEANT interpreter developed by Quantum Research Services, and the OCTAGON package for representing arbitrary shapes in GEANT. Likely future directions of development are described. 2 refs., 7 figs