Re: [ROOT] TGeoMCGeometry vs. TGeoManager

From: Andrei Gheata (Andrei.Gheata@cern.ch)
Date: Wed Apr 14 2004 - 13:19:34 MEST


Hi Peter,

1. Make sure you have the last version of geant3 module from ROOT cvs 
and also update /geom and /geompainter modules if your ROOT version is 
older than 4.00/02
2. Make sure you have added -DWITHROOT to CXXOPTS in 
/geant3/config/Makefile.platform and compile G3 after
3. Your MyMCApplication::ConstructGeometry() method should look like:
{
    TGeoManager::Import("MyGeom.root");
    gMC->SetRootGeometry()
}
  - you do not have to create new TGeoManager as in 
Ex01MCApplication::ConstructMaterials()

4. Maybe adapt your MyApplication::StepManager() and GeneratePrimaries() 
to be sure you 'hit" something.

Let me know,
Andrei



Peter Steinberg wrote:
> 
> Hi everyone (esp. the VMC team) -
> 
> I'm trying to use the geant3 module in ROOT 4-00-03 but am
> having trouble incorporating my own geometry into the examples.
> 
> I've already defined a geometry using the TGeoManager class
> and saved it to a file.  I've then hacked in my geometry into
> the E01 example in geant4_vmc, by reading it in from a file
> (using TGeoManager::Import), but when i run the example i get
> this output:
> 
> ----------------------------------------------------------------------
> 
>  MZLINK.  Initialize Link Area  /GCSLNK/  for Store  0 NL/NS=   100   100
> Geant3 has been created.
> Geometry will be defined via TGeo
> ===> TGeo, Root geometry manager created
> Warning in <TGeoManager::dtor>: deleting previous geometry: TGeo/Root 
> geometry manager
> ===> ,  created
> ### Geometry loaded from file...
> Top volume is TOP. Master volume is TOP
> ### Voxelization retrieved from file
> --- node ID tracking disabled
> ### 195 nodes/ 18 volume UID's in Simple geometry
> ----------------modeler ready----------------
> 
>  Calculating cross section tables, see gphysi.dat for more information
> 
>  Cross section calculation concluded successfully
>  **** GTRIGI: IEVENT=      1 IDEVT=      1 Random Seeds =          0 
>         0
> root [1]
> 
> ----------------------------------------------------------------------
> 
> i.e. it doesn't crash, but nothing happens!  this example works fine
> in its original form, so it's really just the introduction of my
> geometry.
> 
> my main suspicion is that i really should be using the TGeoMCGeometry
> interface from the beginning, but if i check the source, i see that
> the MCGeometry is using the GeoManager anyway.
> 
> so my question is if i really have to rewrite my geometry using
> the TGeoMCGeometry interface, or if there is a way to "import" an
> existing TGeoManager into the TGeoMCGeometry -- or if I am completely
> misunderstanding something!
> 
> Thanks,
> Peter
> 



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