Geant4 User's Guide for Application Developers - Geant4 - CERN

Chapter 8. Visualization8.1. Introduction to VisualizationThe Geant4 visualization system was developed in response to a diverse set of requirements:1. Quick response to study geometries, trajectories and hits2. High-quality output for publications3. Flexible camera control to debug complex geometries4. Tools to show volume overlap errors in detector geometries5. Interactive picking to get more information on visualized objectsNo one graphics system is ideal for all of these requirements, and many of the large software frameworks into whichGeant4 has been incorporated already have their own visualization systems, so Geant4 visualization was designedaround an abstract interface that supports a diverse family of graphics systems. Some of these graphics systemsuse a graphics library compiled with Geant4, such as OpenGL, Qt, while others involve a separate application,such as HepRApp or DAWN.8.1.1. What Can be VisualizedSimulation data can be visualized:• Detector components• A hierarchical structure of physical volumes• A piece of physical volume, logical volume, and solid• Particle trajectories and tracking steps• Hits of particles in detector componentsOther user defined objects can be visualized:• Polylines, such as coordinate axes• 3D Markers, such as eye guides• Text, descriptive character strings, comments or titles• Scales• Logos8.1.2. You have a Choice of Visualization DriversThe many graphics systems that Geant4 supports are complementary to each other.• OpenGL• View directly from Geant4• Requires addition of GL libraries that are freely avialable for all operating systems (and pre-installed on many)• Rendered, photorealistic image with some interactive features• zoom, rotate, translate• Fast response (can usually exploit full potential of graphics hardware)• Print to EPS (vector and pixel graphics)• Qt• View directly from Geant4• Requires addition of Qt and GL libraries that are freely available on most operating systems• Rendered, photorealistic image• Many interactive features• zoom, rotate, translate• Fast response (can usually exploit full potential of graphics hardware)• Expanded printing ability (vector and pixel graphics)214