Discussion on the compilers. One minimal requirement for RH 7.2,7.3
would  be gcc 3.1. 

Federico explained the reason for the change he proposes. The code we
deliver to the users should be easily installable. The Geant4
visualization is not a critical issue.

Ivana. We should not disconnect possibilities without providing a
replacement. The case of the main program has to be corrected, but we
need people to work on. For the moment the backup solution is working
and should be kept. 

Federico. If we have a bug in Geant4 libraries and 
Can we access G4 visualization vie VMC interface? Yes, you have access
all the visualization modules provided in G4. It depends on the
choice, so lets make one of them default and don't bother about the
others.  

Marek. Rene could suggest the best visualization. 

Rene. The various visualization modules have different purpose, so it
is difficult to select one of them with universal scope.

Isidro. OpenGL is not sufficient. You need OpenGL+Motif. For VRML and
DON we need external packages. VRL is very good. 

Federico. Remember, that for some users it is difficult.

Ivana. We are using reflections and many of the visualizations don't
support it. The choice has to take it in the account. 

Rene. The problem with the dynamical linking is probably in the order
of the class initialization. It has to be fixed, either by G4 people
or by us.  

Fed. Proposes to use OpenGL. We need the simplified version with the
sufficient minimum of features. The full version also has to be kept
and we will be happy to have it on the CVS server. 


Ivana. All you require can be achieved easily by changing the
initialization script without touching the structure. 

Fed. It is much easier to debug the new package, it makes the
maintenance easier.  

Ivana. The changes in the makefiles will be done very often in the
geant4vmc, which is not the case in geant4_mc. We always will need
some env. variables to configure.

Marek It must be something wrong with the G4 if we are not able to
configure easily.  

Federico. The main decision has to be that the G4 main program is
removed, and we support one visualization module. Then we ship it to
the users and if the installation passes the tests, everything is OK. 

Rene summarized the discussion between the experts.

OpenScientist is difficult to install.

OpenGL has good navigation, but no picking. It supports
reflections. The OGLIXm version needs Motif or similar package, but
some problems with the dynamical linking are expected. Probably we
need to investigate it. 

DOWN is developed by Japan group 15 years ago for SSC. It supports no
reflections. 

Raytracer has nice features, but is too slow.

GraXML interface in geant4_mc. It is probably the best for 3D
pictures. It looks simple for installation. 

VRML has no support for reflections, but it is going probably to appear.

Federico proposes to start with OGLIX.