Visualization of the geometry

Visualization with legend-pygeom-l200

Simply use legend-pygeom-l200 -V [...] to visualize the full geometry. See GDML viewer for details on how to use the interactive viewer.

If you want to exclude/include components from the 3D rendering, append --assemblies=.... See the section on Geometry options.

The cryostat and LAr volumes are always part of the output, but can be hidden in a scene file, if necessary.

The visualization with the VTK-based viewer can be customized with a scene file, including options for

  • changing volume colors, transparency & hiding volumes

  • better looking renderings (lighting, camera positions, file export)

  • adding a clipper of the geometry (e.g., hiding one half of all volumes)

  • and more tools, also for basic event visualization.

See the scene file format for a reference of the scene file. The scene file can be passed as an argument after -V: legend-pygeom-l200 -V scene.yaml [...].

Visualizing with Geant4/remage (advanced)

The visualization can be exported to Geant4 by using --vis-macro-file=: legend-pygeom-l200 --vis-macro-file=l200-vis.mac l200.gdml [...].

This generated macro does not start any visualization on its own, it just sets the colors. To use it, create a file vis.mac in the same directory:

/run/initialize

/vis/open OGL
/vis/drawVolume lar

/vis/viewer/set/defaultColour black
/vis/viewer/set/background white
/vis/viewer/set/viewpointVector -3 -2 1
/vis/viewer/set/upVector 0 0 1
/vis/viewer/set/rotationStyle freeRotation
/vis/viewer/set/lineSegmentsPerCircle 100

/vis/scene/add/trajectories smooth
/vis/scene/endOfEventAction accumulate

# import the auto-generated visualization attributes from legend-pygeom-l200.
/control/execute l200-vis.mac

and use it with remage remage vis.mac -i -g l200.gdml. It will validate that the given GDML file can be read by Geant4 and show a visualization from it.

It is also possible to use --assemblies= as described above. This will remove any non-specified assembly from the output GDML file. Make sure that you do not overwrite any “production” geometry with this command. Using a file with stripped-down assemblies for a simulation will probably give wrong results.