The Geant4 solid modeler is STEP compliant. STEP is the ISO standard defining the protocol for exchanging geometrical data between CAD systems. This is achieved by standardizing the representation of solid models via the EXPRESS object definition language, which is part of the STEP ISO standard.
The STEP standard supports multiple solid representations. Constructive Solid Geometry (CSG) representations and Boundary Represented Solids (BREPs) are available. Different representations are suitable for different purposes, applications, required complexity, and levels of detail. CSG representations are easy to use and normally give superior performance, but they cannot reproduce complex solids such as those used in CAD systems. BREP representations can handle more extended topologies and reproduce the most complex solids.
All constructed solids can stream out their contents via appropriate methods and streaming operators.
[blyth@belle7 DDDB]$ pwd
/data1/env/local/dyb/NuWa-trunk/dybgaudi/Detector/XmlDetDesc/DDDB
Geant4 VMC represents the realisation of the Virtual Monte Carlo (VMC) for Geant4 . It can be also seen as a Geant4 application implemented via the VMC interfaces. It implements all Geant4 user mandatory classes and user action classes, which provide the default Geant4 VMC behaviour, that can be then customized by a user in many ways.
InStep supports import & export of the following formats: