[Gate-users] Possibly a bug in GATE geometry check?

[John Apostolakis]

Dear Ida,

I write from the perspective of a Geant4 developer - but the 
observations should apply equally to any GATE application.

 - It is unexpected that using visualisation should change the result of 
any geometry check.
 - The results of the recursive_test should be reasonably accurate; that 
is at the limit of high statistics you should get a correct answer, and 
using default number of trial lines you should get an answer which does 
not vary from run to run.

There is another method to check a Geant4 geometry, which involves 
checking every volume which is positioned to see that it does not 
overlap with a volume at the same level or protrude from its parent 
volume.  I am not certain whether this capability is exploited already 
in Gate, in all or recent releases.

Best regards,
John A.

Ida Häggström wrote:
> Dear all,
>
> I've recently posted some questions regarding segmentation violations, 
> geometry test errors and voxelized phantoms. I've experienced a lot of 
> problems with getting a proper run from GATE, and I've spent many 
> hours (piuh!) troubleshooting! =) Anyway, I discovered something that 
> I'm not sure is a bug in GATE or if it's my code that is erroneous...
>
> I run a geometry check as I initialize my run, to check that there are 
> no geometry overlaps etc since I believe this can cause segmentation 
> violations which aborts the entire run.  
> -------------
> /run/initialize
> /geometry/test/recursive_test
> -------------
> I usually keep the visualization disabled since this saves a lot of 
> time for longer runs:
> -------------
> /vis/disable
> -------------
>  I noticed that I get errors regarding my voxelized phantom 
> (overshooting daughter volume) which I don't think should be there 
> (emphasis on THINK!). When I turn the visualization ON however, the 
> errors disappear and I only get results like:
> ----------
> GeomTest: no daughter volume extending outside mother detected.
> GeomTest: no overlapping daughters detected.
> ---------
> from the geometry check. My visualization macro is very simple:
> ----------
> # Visualization.mac
> /vis/open OGLSX
> /vis/viewer/reset
> /vis/drawView 45 45
> /vis/viewer/zoom 2
> /vis/viewer/set/style surface
> /vis/drawVolume
> /tracking/storeTrajectory 1
> /vis/scene/endOfEventAction accumulate
> /vis/viewer/update
> ------------
> and I don't think the visualization should have anything to do with 
> the geometry setup at all?(!) Can this be a GATE bug? Note that the 
> only thing I change in my main macro is changing "/vis/disable" to
> ----------
> #/vis/disable
> /control/execute Visualization.mac
> ----------
> and I get no errors. I've also tried to disable all visualization of 
> the phantom (in the range.dat file, setting visualization to "false") 
> but this has no affect on the run results (no matter if I have the 
> main visualization on or off).
>
> I have attached my main macro, GATE run output log, voxelized phantom 
> macro with related .dat files and a screenshot of my setup with camera 
> and phantom.
>
> Please, if anyone has any idea what could cause these problems, please 
> let me know! I'm really running out of ideas... =) It's not a good 
> option to always have to run with visualization on for longer runs...
> Thanks!
> Ida
>
>
> ------------------------------------------------------------------------
>
> ------------------------------------------------------------------------
>
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