When compiling GEANT4, there are default visualization output. In the past, I used DAWN. DAWN is a static viewer, need to specific view angle, zoom, etc.

Another dynamic viewer is VRML. This is also a built-in visualization output. In the GEANT4 macro, 

/vis/open VRML2FILE
/vis/drawVolume
/vis/scene/add/trajectories
/vis/scene/endOfEventAction accumulate

#generate 10 beams
/run/beamOn 10

GEANT4 will output a g4_XX.wrl file. This file can be opened in any Ubuntu by view3dscene

>sudo apt install view3dscene

After installation, run

>view3dscene g4_XX.wrl

Here is the screenshot of the extended example Testem4

Much better than DAWN.