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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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Example TextGeom
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This example illustrates the use of the text geometry.
1.- GEOMETRY EXAMPLES
Several examples of text geometries are provided:
g4geom_simple.txt :
- Simple construction of materials and single placements
g4geom_matemixt.txt :
- Isotopes, elements and materials
g4geom_boolean.txt :
- Boolean solids
g4geom_reflections.txt :
- Reflections
g4geom_replicas.txt :
- Replicas
g4geom_divisions.txt :
- Divisions
g4geom_paramLinear.txt :
- Linear parameterisations
g4geom_paramSquare.txt :
- Square parameterisations
g4geom_assembly.txt :
- Assembly placements
2.- HOW TO START ?
- execute textGeom in 'batch' mode from macro file
% textGeom run.mac
It will read the geometry from a file named 'g4geom.txt', and it will create a
VRML2 file to visualise the geometry.
Therefore if you want to try any of the above-mentioned files, copy it to a
file with this name,
3.- DEFINING A SENSITIVE DETECTOR
The detector construction class ExTGDetectorConstructionWithSD shows how to
access a volume of the text geometry and assign to it a sensitive detector.
To use it, replace at exampleTextGeom.cc the line
runManager->SetUserInitialization(new ExTGDetectorConstruction);
by
runManager->SetUserInitialization(new ExTGDetectorConstructionWithSD);
and recompile.
It will use the geometry from the file 'g4geom_SD.txt'
4.- MIXING TEXT AND C++ GEOMETRIES
The detector construction class ExTGDetectorConstructionWithCpp shows how to
create a volume with C++ and place it in the world or inside a volume defined
in the text geometry.
To use it, replace at exampleTextGeom.cc the line
runManager->SetUserInitialization(new ExTGDetectorConstruction);
by
runManager->SetUserInitialization(new ExTGDetectorConstructionWithCpp);
and recompile.
It will use the geometry from the file 'g4geom_simple.txt'
5.- CREATING NEW TAGS IN THE TEXT GEOMETRY: DEFINING CUTS PER REGION
The detector construction class ExTGDetectorConstructionWithCuts, together with
ExTGRCLineProcessor, ExTGRCDetectorBuilder, ExTGRCRegionCutsMgr and
ExTGRCRegionData show how to add a couple of tags, ':REGION' and ':CUT', that
allow to define cuts per region in your input geometry text file.
To use it, replace at exampleTextGeom.cc the line
runManager->SetUserInitialization(new ExTGDetectorConstruction);
by
runManager->SetUserInitialization(new ExTGDetectorConstructionWithCuts);
and recompile.
It will use the geometry from the file 'g4geom_cutsPerRegion.txt'
6.- DUMP THE IN-MEMORY GEOMETRY TO TEXT FILE
The run action 'ExTGRunAction' triggers the writing of the in-memory Geant4
geometry to a text file.
To use it you just have to uncomment in exampleTextGeom.cc the line
runManager->SetUserAction(new ExTGRunAction);
and it will read the geometry from the file 'g4geom.txt' and will write the
geometry in a file named 'geom.txt'
Gabriele Cosmo