Why volume numbers has changed in Jason geometry file?

The number of nested volumes (nv),
is the total number of parent volumes for the sensitive volume
(sensitive volume is indicated by the HITS in the tree structure below).

For the Jason and CVS files this nv number seems to be the same
(see block tree structures below).
Then why volume ids id in g2t tables has changed?

The answer I found (which seems trivial to me know)
is that in the original (CVS) file ECAL
block has been instantiated (positioned) twice.
The second appearance is the prototype (East) version of the Endcap
(Original ecalgeo.g from CVS)

        if (emcg_OnOff==1 | emcg_OnOff==3) then
             Position ECAL in CAVE z=+center
        endif
        if (emcg_OnOff==2 | emcg_OnOff==3) then
             Position ECAL in CAVE z=-center ThetaZ=180
        endif

In Jason version the second appearance has been removed
(what seems natural and it should not have any effect)
(ecalgeo.g Jason edits, g23):

        IF (emcg_OnOff>0) THEN
           Create ECAL

              .....

        IF (emcg_OnOff==2 ) THEN
           Prin1
             ('East Endcap has been removed from the geometry' )
        ENDIF               EndIF! emcg_OnOff

Unfortunately, this affects the way GEANT counts nested volumes

(effectively the total number was reduced by 1, from 8 to 7)

and this is the reason why the volume numbering scheme

in g2t tables has been affected.

I propose to put back these East Endcap line back,

since in this case it  will not require any additional

changes to the EEMC decoder and g2t tables.

Block tree of the geometry file

blue - added volumes in Jason file
red - G10 volume removed in Jason file
HITS - sensitive volumes

 ---- Jason file ----

ECAL
 EAGA
  |EMSS
  |  -EFLP
  |  |ECVO
  |  |  |EMOD
  |  |  |  |ESEC
  |  |  |  |  |ERAD
  |  |  |  |  | -ELED
  |  |  |  |  |EMGT
  |  |  |  |  |  |EPER
  |  |  |  |  |  |  |ETAR
  |  |  |  |  |  |  |  -EALP
  |  |  |  |  |  |  |  -ESCI -> HITS
  |  |ESHM
  |  |  |ESPL
  |  |  |  |EXSG
  |  |  |  |  -EXPS
  |  |  |  |  -EHMS -> HITS
  |  |  |  |  -EBLS
  |  |  |  |  -EFLS
  |  |  |ERSM
  |  -ESSP
  |  -ERCM
  |  -EPSB
  |ECGH
  |  -ECHC

---- CVS file ----
ECAL
 EAGA
  |EMSS
  |  -EFLP
  |  |ECVO
  |  |  |EMOD
  |  |  |  |ESEC
  |  |  |  |  |ERAD
  |  |  |  |  | -ELED
  |  |  |  |  |EMGT
  |  |  |  |  |  |EPER
  |  |  |  |  |  |  |ETAR
  |  |  |  |  |  |  |  -EALP
  |  |  |  |  |  |  |  -ESCI -> HITS
  |  |ESHM
  |  |  |ESPL
  |  |  |  |EXSG
  |  |  |  |  -EHMS -> HITS
  |  |  |  -EXGT
  |  |  -ERSM
  |  -ESSP
  |  -ERCM
  |  -EPSB
  |ECGH
  |  -ECHC

Block definitions

Jason geometry file 

Create ECAL

Block ECAL is one EMC EndCap wheel
  Create and Position EAGA AlphaZ=halfi
EndBlock

Block EAGA IS HALF OF WHEEL AIR VOLUME FORTHE ENDCAP MODULE
  Create AND Position EMSS konly='MANY'
  Create AND Position ECGH alphaz=90 kOnly='ONLY'
EndBlock

Block EMSS is the steel support of the endcap module
  Create AND Position EFLP z=zslice-center+zwidth/2
  Create AND Position ECVO z=zslice-center+zwidth/2
  Create AND Position ESHM z=zslice-center+zwidth/2 kOnly='MANY'
  Create AND Position ECVO z=zslice-center+zwidth/2
  Create AND Position ESSP z=zslice-center+zwidth/2
  Create ERCM
  Create EPSB
EndBlock

Block ECVO is one of endcap volume with megatiles and radiators
  Create AND Position EMOD alphaz=d3 ncopy=i_sector
EndBlock

Block ESHM is the shower maxsection
  Create and Position ESPL z=currentk Only='MANY'
  Create ERSM
EndBlock

Block ECGH is air gap between endcap half wheels
  Create ECHC
EndBlock

Block ECHC is steel endcap half cover
EndBlock

Block ESSP is stainless steelback plate 
EndBlock

Block EPSB IS A PROJECTILE STAINLESS STEEL BAR
EndBlock

Block ERCM is stainless steel tie rod in calorimeter sections
EndBlock

Block ERSM is stainless steel tie rod in shower max
EndBlock

Block EMOD (fsect,lsect) IS ONE MODULEOF THE EM ENDCAP
  Create AND Position ESEC z=section-curr+secwid/2
EndBlock

Block ESEC is a single em section
  Create AND Position ERAD z=length+(cell)/2+esec_deltaz
  Create AND Position EMGT z=length+(gap+cell)/2+esec_deltaz
  Create AND Position ERAD z=length+cell/2+esec_deltaz
EndBlock

Block EMGT is a 30 degree megatile
  Create AND Position EPER alphaz=myPhi
EndBlock

Block EPER is a 5 degree slice of a 30 degree megatile (subsector)
  Create and Position ETAR x=(rbot+rtop)/2ort=yzx
EndBlock

Block ETAR is a single calorimeter cell, containing scintillator, fiber router, etc...
  Create AND Position EALP y=(-megatile+emcs_alincell)/2
  Create AND Position ESCI y=(-megatile+g10)/2+emcs_alincell _
EndBlock

Block ESCI is the active scintillator (polystyrene) layer
EndBlock

Block ERAD is the lead radiator with stainless steel cladding
  Create AND Position ELED 
EndBlock

Block ELED is a lead absorber plate
EndBlock

Block EFLP is the aluminum (aluminium) front plate of the endcap
EndBlock

Block EALP is the thin aluminium plate in calorimeter cell
EndBlock

Block ESPL is the logical volume containing an SMD plane
  Create and Position EXSG alphaz=d3 ncopy=isec kOnly='MANY'
  Create and Position EXSG alphaz=d3 ort=x-y-z ncopy=isec kOnly='MANY'
  Create and Position EXSG alphaz=d3 ncopy=isec kOnly='MANY'
  Create and Position EXSG alphaz=d3 ort=x-y-z ncopy=isec kOnly='MANY'
  Create and Position EXSG alphaz=d3 ncopy=isec kOnly='MANY'
EndBlock

Block EXSG Is another logical volume... this one acutally creates the planes
  Create and Position EXPS kONLY='MANY'
  Create and Position EHMS x=xc y=yc alphaz=-45 kOnly='ONLY'
  Create and Position EBLS x=xc y=yc z=(+esmd_apex/2+esmd_back_layer/2) alphaz=-45 kOnly='ONLY'
  Create and Position EHMS x=xc y=yc alphaz=-45 ort=x-y-z kOnly='ONLY'
  Create and Position EFLS x=xc y=yc z=(-esmd_apex/2-esmd_front_layer/2) alphaz=-45 ort=x-y-z kOnly='ONLY'
EndBlock

Block EHMS defines the triangular SMD strips
Endblock! EHMS

Block EFLS is the layer of material on the front of the SMD planes
EndBlock! EFLS

Block EBLS is the layer of material on the back of the SMD planes
EndBlock! EFLS

Block EXPS is the plastic spacer in the shower maximum section
EndBlock

CVS geometry file 

Create ECAL

Block ECAL is one EMC EndCap wheel
  Create and Position EAGA AlphaZ=halfi
EndBlock

Block EAGA is half of wheel air volume forthe EndCap module
  Create and Position EMSS konly='MANY'
  Create and Position ECGH AlphaZ=90 konly='ONLY'
EndBlock

Block EMSS is steel support of the EndCap module
  Create and Position EFLP z=zslice-center+slcwid/2
  Create and Position ECVO z=zslice-center+slcwid/2
  Create and Position ESHM z=zslice-center+slcwid/2
  Create and Position ECVO z=zslice-center+slcwid/2
  Create and Position ESSP z=zslice-center+slcwid/2
  Create ERCM
  Create EPSB
EndBlock

Block ECVO is one of EndCap Volume with megatiles and radiators
  Create and Position EMOD AlphaZ=d3 Ncopy=J_section
EndBlock

Block ESHM is the SHower Maxsection
  Create and Position ESPL z=current
  Create ERSM
Endblock

Block ECGH is air Gap between endcap Half wheels
  Create ECHC
EndBlock

Block ECHC is steel EndCap Half Cover
EndBlock

Block ESSP is Stainless Steelback Plate 
endblock

Block EPSB is Projectile Stainless steel Bar
endblock

Block ERCM is stainless steel tie Rod in CaloriMeter sections
endblock

Block ERSM is stainless steel tie Rod in Shower Max
endblock

Block EMOD is one moduleof the EM EndCap
  Create and Position ESEC z=section-curr+secwid/2
endblock

Block ESEC is a single EM section
  Create and Position ERAD z=len + (cell)/2
  Create and Position EMGT z=len +(gap+cell)/2
  Create and Position ERAD z=len + cell/2
Endblock

Block EMGT is a megatile EM section
  Create and Position EPER AlphaZ=(emcs_Nslices/2-isec+0.5)*dphi
Endblock

Block EPER is a EM subsection period (super layer)
  Create and Position ETAR x=(RBot+RTop)/2ORT=YZX
EndBlock

Block ETAR is one CELL of scintillator, fiber and plastic
  Create and Position EALP y=(-mgt+emcs_AlinCell)/2
  Create and Position ESCI y=(-mgt+G10)/2+emcs_AlinCell _
EndBlock

Block ESCI is the active scintillator (polystyren) layer
endblock

Block ERAD is radiator 
  Create and PositionELED 
endblock

Block ELED is lead absorber Plate 
endblock

Block EFLP is First Aluminium plate 
endblock

Block EALP is ALuminiumPlate in calorimeter cell
endblock

Block ESPL is one of the Shower maxPLanes
  Create and position EXSG AlphaZ=d3Ncopy=isec
  Create and position EXSG AlphaZ=d3Ncopy=isec
  Create and position EXGT z=msecwd AlphaZ=d3
  Create and position EXSG AlphaZ=d3 ORT=X-Y-Z Ncopy=isec
  Create and position EXGT z=-msecwd AlphaZ=d3
  Create and position EXSG AlphaZ=d3Ncopy=isec
  Create and position EXGT z=msecwd AlphaZ=d3
  Create and position EXSG AlphaZ=d3 ORT=X-Y-Z Ncopy=isec
  Create and position EXGT z=-msecwd AlphaZ=d3
Endblock

Block EXSG is the Shower maxGap for scintillator strips
  Create EHMS
endblock

Block EHMS is sHower Max Strip
Endblock

Block EXGT is the G10 layer in the Shower Max
EndBlock