

This example demonstrates integration of the navigation elements of
[VecGeom](https://gitlab.cern.ch/VecGeom/VecGeom), to investigate the
performance benefits.

This integration is in development. Supporting Placement volumes -- other
volumes would be handled by existing Geant4 navigation.

The example loads a GDML file for the geometry, and can execute a batch
file (vecgeomNav.in) or run interactive commands or both.

# Installation / Configuration

## Dependencies

In addition to Geant4, two projects: are required VecGeom and G4VecGeomNav.
VecCore is also required, but can be found through VecGeom.

It is optionally possible to use Root in G4VecGeomNav to store voxel
information for safety computation.  These can require significant computation
to calculate if at least one logical volume contains many daughter volume.

## Configuration
- To configure you must set:

     setenv CMAKE_PREFIX_PATH "${VECCORE_DIR}:${VECGEOM_DIR}"

or if you are using Vc from Root
     setenv CMAKE_PREFIX_PATH "${ROOTSYS}:${VECGEOM_DIR}"
where VecGeom has also been built with the same installation of Vc from Root.

