Visualization with OpenGL-Qt

Visualizations using opengl allow graphics to be rendered and adjusted real-time in a relatively performant way. One can visualize the whole detector or slices of the detector with particle tracks to debug / demonstrate the detector.

Setting up GEANT4

In your mac directory you should create a file called vis.mac. This file will hold all of your visualization information. Here is an example:

/glg4debug/glg4param omit_muon_processes  1.0
/glg4debug/glg4param omit_hadronic_processes  1.0

/run/initialize

/vis/open OGLSQt
/vis/scene/create
/vis/scene/add/trajectories #additionally can add rich and/or smooth
/tracking/storeTrajectory 1
/tracking/FillPointCont 1
/vis/scene/add/volume
/vis/scene/add/hits
/vis/sceneHandler/attach

/vis/viewer/set/upVector 0.0 0.0 1.0
/vis/viewer/set/viewpointThetaPhi 90 180
/vis/viewer/zoomTo 20
/vis/viewer/set/style s

## Cut a plane through the detector
/vis/viewer/addCutawayPlane -100 0 0 cm 1 0 0

Running rat

In order to keep rat from exiting the moment the macro completes, place rat into interactive mode. This can either be done standalone:

rat -

Or even in combination with a list of macros::

rat vis.mac -

The import part is to remember the “-” which places rat into interactive mode.