Problem 2206

Summary:	Stuck Track in G4Ellipsoid
Product:	Geant4	Reporter:	John.Allison
Component:	geometry	Assignee:	Evgueni.Tcherniaev
Status:	RESOLVED FIXED
Severity:	minor
Priority:	P4
Version:	other
Hardware:	Apple
OS:	Mac OS X

Description John.Allison 2019-11-29 13:27:56 CET

Running on current master...

If I run examples/advanced/human_phantom with 
/gps/position 0 0 40 cm
/gps/pos/type Point
/gps/ang/type iso
/gps/particle gamma
//run/beamOn 10
I get GeomNav1002 below for several of the events. Occasionally I get “time going backwards” as well. There are no overlaps nearby

If I change G4Elilpsoid to a G4Box, all’s well.

Note: (0,0,40) cm is right on a corner of the G4Ellipsoid in G4MIRDPancreas.cc. A zcut makes the corner.

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomNav1002
issued by : G4Navigator::ComputeStep()
Stuck Track: potential geometry or navigation problem.
Track stuck, not moving for 10 steps.
Current phys volume: 'physicalPancreas'
- at position : (0,0,400)
in direction: (-0.7590753513494927,0.2292508358073039,0.609301785041942)
(local position: (30,-6.123233995736764e-15,7.960204194457785e-15))
(local direction: (0.6093017850419421,-0.229250835807304,-0.7590753513494926)).
Previous phys volume: 'physicalTrunk'
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 -------

Comment 1 Gabriele Cosmo 2019-11-29 13:48:54 CET

Can you please specify what version of Geant4 you're running on?
Are you running on the current Master?

Comment 2 Gabriele Cosmo 2019-11-29 13:49:34 CET

OK, I now see it. You are on the Master...

Comment 3 Gabriele Cosmo 2019-12-05 09:23:09 CET

There is a Merge Request, currently under testing (https://gitlab.cern.ch/geant4/geant4-dev/merge_requests/710), where a bug in the geometry setup of the MIRD phantom has been fixed...
John, can you see if that makes a difference?

Comment 4 John.Allison 2019-12-05 10:14:06 CET

Already tried it. It makes no difference. The MR is an unrelated problem (I have been in touch with Susanna).

John

Comment 5 Gabriele Cosmo 2019-12-19 09:19:07 CET

The problem has been fixed by Evgueni and the fix is pushed to the current Master.
It will be included in the next patch release.