[Gate-users] Overlaping problem

[Marc Verderi]

Hello,

The problem is that the first case was already "illegal". In Geant4, 
daughter volumes should be fully contained in their mother volume. The 
geometry does not detect 100% of the times problems like this, but 
absence of complains, does not mean absence of problems... you may end 
up with unexpected behaviours in the case you describe, and, to make it 
clear, the situation you describe, in the Geant4 view, is a bug of your 
geometry.

Can you make your box large enough to contain the cones ? (ie do you 
have enough room for this ?). If so, this could be a solution and you 
should just take care of putting the right material in this box, to get 
the same physical results. But in your case, I think the solution you 
would prefer is the "assembly" (I don't know if Gate makes use of this) 
: this is a just an "immaterial" frame in which you place volumes, and 
that you place, to have, as you do, an "all together" placement of 
volumes. This is an utility class, and once the volumes are placed, this 
frame "disappears" and has not existence for the tracking.

Cheers,
Marc

Gilberto Almeida a écrit :
> Hello gate-users
>
>  I'm having a strange problem... I have set 2 cones with: Rmin1 0. cm, 
> Rmax1 2.5 cm, Rmin2 0. cm, Rmax2 3.17 cm, setHeight 5 cm inside a box 
> of 0.1x0.1x0.1nm (to be able to rotate both cone without changing the 
> alignement)and the macro works fine. The problem is: when I use 2 
> cones with: Rmin1 0. mm, Rmax1 0.5 mm, Rmin2 0. mm, Rmax2 0.634 mm, 
> setHeight 0.5 mm, in the very same macro, it returns :
>
> "Start closing geometry.
> PANIC! - G4SmartVoxelHeader::BuildNodes()
>          Daughter physical volume cone1_P
>          is entirely outside mother logical volume pinhole_L !!
>  
> *** G4Exception : InvalidSetup
>       issued by : G4SmartVoxelHeader::BuildNodes()
> Overlapping daughter with mother volume.
> *** Fatal Exception *** core dump ***
>  
> *** G4Exception: Aborting execution ***
> Abort"
>
>  My question is why? If in the first case the dimensions are far more 
> different than in those ones in the second case. The only changes in 
> all script are in the dimensions of the cones, nothing else.
>
>  Or is there another way to rotate the two cones conected by the appex?
>
>  Thank you for any help
>
> Best regards,
>
> Gilberto Almeida
> Instituto de Biofísica e Engenharia Biomédica
> Faculdade de Ciências da Universidade de Lisboa
> Campo Grande
> 1749-016 Lisboa, Portugal
>
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