====== Geometry ======

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.

===== Compiling and creating a root geometry file =====

In order to create the root geometry files, go to the according directory and do:
<code>
cd primasoft/geant4/geometry
cmake .
make
</code>
Now your output should be something like this:
<code>
[ 45%] Built target PrimaGeom
[ 63%] Built target test_proto16
[ 81%] Built target build_tchamber
[100%] Built target build_proto16
</code>
Here, the executables are listed.
By executing for example:
<code>
./build_tchamber 
</code>
the file targetChamber.root is created, which can be used in the simulation.


===== How to include a new part =====
  -  Check for the material you want to use in PRIMAMaterials.h and PRIMAMaterials.cc. If the material does not exist, add it
  -  Make a new .h and .cc file according to PRIMAProto16Constructor, where the geometry of your object is defined
  -  Create a new build.cxx, where your new TGeoVolumeAssembly is included
  -  Modify your CmakeLists.txt
  -  Make and execute your new executable → a new .root file is created
    - Use  cmake --build.  and ./"your executable here"

Useful links:
  * [[https://root.cern.ch/how/how-draw-objects|how-to-draw-objects]]
  * [[https://root.cern.ch/root/htmldoc/guides/users-guide/ROOTUsersGuide.html#the-geometry-package|geometry-package]]
  * [[https://cmake.org/cmake/help/latest/guide/tutorial/index.html]]
  * [[https://root.cern.ch/root/htmldoc/guides/users-guide/Geometry.html]]


==== Have a look at the geometry ====

To check, weather your geometry is correct, have look at it. Open the root file and the TBrowser:
<code>
primasoft/geant4/geometry$ root -l targetChamber.root 
root [1] TBrowser b
</code>
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.

== Scene interaction with 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.