The geometry files (which are root files) can be found in primasoft/geant4/geometry. The geometry you want to use in your simulation can be set in the primaf4sim.conf file.

In order to create the root geometry files, go to the according directory and do:

cd primasoft/geant4/geometry
cmake .
make

Now your output should be something like this:

[ 45%] Built target PrimaGeom
[ 63%] Built target test_proto16
[ 81%] Built target build_tchamber
[100%] Built target build_proto16

Here, the executables are listed. By executing for example:

./build_tchamber 

the file targetChamber.root is created, which can be used in the simulation.

1. Check for the material you want to use in PRIMAMaterials.h and PRIMAMaterials.cc. If the material does not exist, add it
2. Make a new .h and .cc file according to PRIMAProto16Constructor, where the geometry of your object is defined
3. Create a new build.cxx, where your new TGeoVolumeAssembly is included
4. Modify your CmakeLists.txt
5. Make and execute your new executable → a new .root file is created
   1. Use cmake –build. and ./“your executable here”

Useful links:

• how-to-draw-objects
• geometry-package
• https://cmake.org/cmake/help/latest/guide/tutorial/index.html
• https://root.cern.ch/root/htmldoc/guides/users-guide/Geometry.html

To check, weather your geometry is correct, have look at it. Open the root file and the TBrowser:

primasoft/geant4/geometry$ root -l targetChamber.root 
root [1] TBrowser b

Now open the folders until you can see the different Volume folders.
With a right-click on for example Master Volume you can select Draw and a new window will be opened. Enter “ogl” as option and press “OK”. Now your geometry is displayed by the GL viewer.

• Left mouse button: ROTATE (ORBIT) the scene by holding the mouse button and moving the mouse
• w: wireframe mode
• e: switch between dark/light color-set
• r: filled polygons mode
• t: outline mode

More interaction modes are explained in the help menu.