A. Sailer, C. Vuosalo, F. Gaede, I. Osborne, M. Petric, M. Frank, T. Madlener, V. Voelkl

1)   Pending problems
1.1) Pending problems reported by Sang Hyun Ko:
     - Cannot setup Birk's constant as material property.
     - No analogy to G4PVParametrized. Unclear if a solution is possible.
1.2) Add GFlash parameterisation to DDG4 (issue #802).
1.3) CMS problem with subtraction - cause not confirmed. Needs further investigation

2)    Closed issues and fixed problems
2.1) Output of shapes in as CAD files (issue #813).
2.2) Significant memory increase of GeoHandler from v01-15 #820

3) Round table
   Markus:     See above
   Ianna:        -
   Carl:          - Need fix to Geant4AssemblyVolume.
                     - Somehow unstable results from simulation.
                       In ~ 10 % of the cases results are not bit-wise identical.
                     - PowerPC builds are particularly sensitive to exceptions and SEGVs.
                       Difficult to debug.
   Andre:       A lot of user support. Some fixes to DDSim to allow for user supported
                     physics constructors.
   Marko:      Merged beginners manual merged.
   Thomas:     -
   Valentin:    -
   Frank:        -

4) AOB

Next meeting in 3 weeks: 27/05/2021