g4view is a scientific application that permits to read geometry files at the Geant4 GDML format describing particle physics detectors. g4view permits to visualize the geometry of a loaded detector. From the main menu, you can then start a "particle through matter" simulation of the detector by using the Geant4 toolkit. g4view is fully scripted (including the main GUI panel) and scriptable/customizable by using the embedded insh bash shell like interpreter. g4view can also read and execute g4mac files containing Geant4 scripting commands. Under the examples menu, there are predefined typical setups as a piece of an electromagnetic calorimeter intended to be used for particle physics detector teaching. We recall that Geant4 is a particle through matter simulation toolkit heavily used in high energy physics (for example at the CERN LHC experiments), but also for spatial and medical science.
The code is based over the Geant4 core and the softinex inlib/exlib C++ classes. The code is highly portable (macOS, Linux, Windows but also iOS, Android, WebAssembly) and a WebAssembly version is available straight from the web pages.
WARNING: a Geant4 geometry tree could be something fat to process due to the "russian dolls" structure that may induce a lot of volumes. If attempting to run on smartphones or tablets you will be able to do a lot but do not ask too much...
You can have a demo on YouTube on the "Guy Barrand" channnel, and the general behaviour of the app is described in the "App general behaviour" section of the softinex portal.