If you built and installed Geant4 configured with the option GEANT4_INSTALL_DATA set, then the Geant4 datasets will have been downloaded and installed automatically.

In this case, the geant4.(c)sh and geant4make.(c)sh scripts will set up the needed environment variables required by Geant4 to locate these datasets. On Windows, you will need to set the needed environment variables listed below by hand. This can be done as follows

If you chose not to install the datasets, but require them later, the geant4-config program may be used to install them on Unix platforms via its --install-datasets argument. This is documented in Section 3.2.3.

On Windows platforms, you will need to download and unpack them by hand to the location you specified for GEANT4_INSTALL_DATADIR. If you did not set this, it defaults to CMAKE_INSTALL_PREFIX/share/Geant4-10.0.0/data. Unpacking the datasets in this location will result in Geant4 automatically locating them once geant4.(c)sh or geant4make.(c)sh have been sourced.

If you have datasets in a different location, then you will need to manually set the following environment variables:

In Geant4 10.0, a new dataset G4ENSDFSTATE1.0 has been introduced. Whilst this dataset is downloaded and installed for convenience, it is only required in a few special use cases described in the Geant4 Guide for Toolkit Developers. It is therefore not configured by default (meaning that the environment variable pointing to the data is not set) and you should not do so unless your application has the specific use cases discussed in that guide. Please see the Application Developer's Guide for information about these use cases and how to configure the use of G4ENSDFSTATE1.0.