Stuck Track: potential geometry or navigation problem

Geometry, Fields and Transportation
1

I build a 500nm cube with a 100nm sphere inside. The warning message always pops up at runtime as follows，and the program will suddenly stop running, should I modify the physical process or geometry ?

*** G4Exception : GeomNav1002
issued by : G4Navigator::ComputeStep()
Stuck Track: potential geometry or navigation problem.
Track stuck, not moving for 10 steps.
Current phys volume: ‘WaterCubePhysVol’

  • at position : (0,0,2.272489531138023e-05)
    in direction: (-0.7861613457480034,-0.5962365404035369,0.1626417115604408)
    (local position: (0,0,2.272489531138023e-05))
    (local direction: (-0.7861613457480034,-0.5962365404035369,0.1626417115604408)).
    Previous phys volume: ‘SpherePhysVol’

Likely geometry overlap - else navigation problem !
*** Trying to get unstuck using a push - expanding step to 1e-07 (mm) … Potential overlap in geometry !

*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------

2

Those are very small structures. How are you placing the sphere inside the cube? Also what cuts, if any, are you applying to particles?

3

This problem has been solved for the input circumference rate is 3.14.