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None GDML Geometry into GEANT4 solution!! 

Forum: Geometry
Date: 11 Mar, 2008
From: Francisco Garcia <Francisco Garcia>

Dear Geant4 Users,

I have found a tracking problem with GDML parsed geomtries. I have shown in the 5th Geant4 workshop in Tokyo how to solve this problem, but I think many of you do not know yet.

This problem has happen with many people during simulation that the the tracking do not see the geometry itself.

to solve this you need to do next steps:

1.- The very first volume in the placement has to be positioned with coordinates x=0, y=0, z=0
as for instance the ECfG4.

 </structure>
     .
     .
  <volume name="World" >
   <materialref ref="Air" />
   <solidref ref="WorldBox" />
   <physvol>
    <volumeref ref="ECfG4" />
    <positionref ref="t18649" />
    <rotationref ref="r7" />
   </physvol>
     .
     .
     .
  </volume>
 </structure>

2.- The coordinates of this first volume must look like this

 <define>
    .
    .
  <position name="t18649" unit="mm" x="0" y="0" z="0" />
    .
    .
 </define>

My suspicion is the world volume for some reason takes this coodinates as his own and if they are not in 0,0,0 then it mess up the full tracking.

I tried different work around but I succeed only by creating a new GDML file where make a new box located in 0,0,0 and then call an external file which is the file where the whole geometry is.
This works but you cannot return the name of the full geometry mother volume.

I did not Succeed when I create the world volume in the Detector Constructor using CSG volumes and then parse the whole geometry from the GDML file, the result was that the world volume is empty.

I did not succeed when I tried to set next parameters to the world volume, look bellow.

<positionref ref="txxxx" />
<rotationref ref="rx" />


Ok!!! I hope this can help somebody and also I very much would like that somebody makes the changes in the software to remove this problems

Cheers,

Francisco

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1 None: Re: GDML Geometry into GEANT4 solution!!   (Zoltan - 12 Mar, 2008)
(_ None: Re: GDML Geometry into GEANT4 solution!!   (Francisco Garcia - 12 Mar, 2008)
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