From: Matthias Schroeder [Matthias.Schroder@cern.ch]
Sent: Monday, May 21, 2001 10:49 AM
To: John.Apostolakis@cern.ch
Cc: Albert.de.Roeck@cern.ch
Subject: CMS Request for Reflections

Dear John,

at least one of the sub-detector groups in the CMS collaboration want
to build the detector descriptions for test-beams and the real
detector from EUCLID. For this to work, reflections will have to be
implemented in GEANT4. We thus ask the GEANT4 collaboration to implement
reflections, allowing to describe any part of the detector to be
defined as a reflection of an already described part. This reflection
should give a proper description independent of the complexity of the
reflected geometry.

We would also like to ask for better tools for debugging of geometry
descriptions. We noticed the need for a more powerful tool to detect
problems like volume overlaps and invalid descriptions (e.g. placement
of volumes inside parametrised volumes). We even need a basic tool
allowing to simply display a volume hierarchy, allowing to show the
characteristics of some or all volumes within that tree.

Best regards,

Matthias Schroder