A new Geant4 modeling solution based on CAD geometries

A new software system has been developed for converting CAD (Computer-Aided Design) models to Geant4 geometries. It converts CAD to two solids types - Constructive Solid Geometry (CSG) and tessellated solids. The CAD-to-CSG conversion is based on a newly developed half-space solid type, which represents exactly the CAD solids using analytical surfaces. The CAD conversion to the tessellated solids uses triangular facets to approximate the CAD solids. These two solid types can be hybrid used in one Geometry Description Mark-up Language (GDML) file. In addition, the system provides comprehensive CAD modeling capabilities, including CAD viewing, organizing, modification, etc. It has been verified using complex test cases, and has been distributed as an open source code.