Problem 214

Summary:	Placement and Replica don't give same tracking information
Product:	Geant4	Reporter:	ob214
Component:	geometry	Assignee:	Gabriele Cosmo <Gabriele.Cosmo>
Status:	RESOLVED INVALID
Severity:	normal
Priority:	P2
Version:	other
Hardware:	PC
OS:	Linux

Description ob214 2001-02-01 11:04:57 CET

I placed some volumes using G4PVReplica. I used a width slightly larger than
the width of the volumes placed therefore leaving a gap between them.
Now, If I fire a particle in the gap and use /tracking/verbose the particle is
said to go through the placed volume instead of its mother.
If I place the volumes "by hand" with G4PVPlacement then I get the right result.
I was describing my geometry using several layer of volumes placed with
G4PVReplica (I think it's correct to place a volume with Replica in a volume
already placed with Replica?) but it turned out that the tracking system says
that the particle is in a volume instead of a gap (the mother).
Worse, it seems to cause an infinite loop (see another report: infinite
transportation).

Comment 1 Gabriele Cosmo 2001-02-02 07:14:59 CET

*** Bug 213 has been marked as a duplicate of this bug. ***
*** 'Gabriele.Cosmo@cern.ch' will be responsible for bug 213. ***

Comment 2 Gabriele Cosmo 2001-02-02 07:47:59 CET

As specified in section 3.6.4.2 of the User's Guide for Application
Developers for 'Repeated volumes', it is not possible to add daughter volumes
to replicated volumes if the size or type of solids varies (this actually
needs to be generalised in the documentation to both parameterised volumes
and replicas... thanks for pointing this out!). Doing so, will lead to
unpredictable behavior. It looks like the specifications given to G4PVReplica
in your geometry are not correct, since there cannot be 'gaps' inside a replica
- a replica is a 'slicing' of the mother volume and the whole of the mother
volume must be sliced.
In case this diagnosis is not correct, please provide us a snippet of code with
the geometry you defined so we can easily check and in case reproduce the
problem.