DD4hep Meeting November 27th, 2025

Present:     Juan, Markus, Peter, Andre, Thomas

Apologies: 

Link to minutes of previous meeting

Merged PRs

• PR1498: Modernize code related to Surfaces and the SurfaceManager (Juan)
• PR1518: Fix configure warnings about CMake policies CMP0167 and CMP0177 (Juan)
• PR1519: Update command setters to use different separator in makeList (Stefano Fanchellucci)
• PR1521: Remove more from __future__ import (Juan)
• PR1522: Remove from .gitignore existing folders in the repository (Juan)
• PR1523: Fix flake8 errors in two files (Juan)
• PR1525: Fix to issue  #1524 (Markus)
  ISSUE1524: Assemblies badly taken into account when building volumes
• PR1526: Add a --gdb argument to ddsim to attach gdb
• PR1528: Add support to close the geometry with voxelization OFF
  ISSUE1527: Add support to close the geometry with voxelization OFF

Closed PRs, closed issues and fixed problems

• None

Pending Problems

• ISSUE1297:  Possible to dump all available readout elements?
                        ==> Possibly a copy of unsolved ISSUE580 from Valentin about enumerating all sensitive cells.
• ISSUE1320:  Replacing a Handle<Segmentation> which contains a MultiSegmentation with the underlying Segmentation
                        ==> Unclear what he really means.
• ISSUE1335:   Uniform random picking of points on detector surfaces for noise studies
                         This problem is linked to #1297 and #580.
• ISSUE1373:  Add GeneratorInfo to EDM4hepReader (Andre)
• ISSUE1443:  Make user particle handler extensible
                         ---> Maybe we should take advantage and re-collect requirements.
• ISSUE1458: XML file vs TGeoStored geometry in GenFit
• ISSUE1487: The test t_DDDigi_sim_test_weighted_deposit_overlay can fail (Juan)
    ---> Unstable test 
• ISSUE1489:  using SkinSurfacequestion
                        ----> Issue re-opened by Sara Eno
                        ----> Does she have a problem with the interface ?
• ISSUE1492:  Readout segmentation for multiple cylinders with offset axes question
                        ----> Unclear code in CylindricalGridPhiZ.cpp line 80
                        ----> Try special case where axis is identical to beam axis.
• ISSUE1501: Bug/Feature: Condense duplicated particle contributions in calorimeter question
• ISSUE1514: How to convert Geant4TrackID into MCParticle Parent ID

• ISSUE1515: How to apply the step_length_max limit to neutral particles?
                        ----> Issue opened by Andreas Loeschke
  New:
• ISSUE1520: Missing segmentation in the box of straws (Juan)
                        -----> This detector has intentionally no segmentation, because the sensitive volumes should not enter the volume manager since there are so many....
                         Sensitive detector is attached to main gas volume, which perhaps is wrong: It should not be attached to any volume.
                         There are 2 tests related to BoxOfStraws. Not both seem to fail. Maybe the problem is related to the DDSim setup in the second test?
  
  Pending PR:
• PR1240:        Add multithreading support to ddsim
• PR1314:        Cylinder segment surface (Armin Ilg)
• PR1503:        [WIP] Add flag for fast simulation to MCParticle (Thomas)

Round Table

Juan:.     NTR
Markus:  NTR
Peter:      NTR
Andre:     ROOT is released and Geant5 comes December 5th. Afterwards we make a new release for LHCb. 
Thomas: NTR

AOB

Next meeting:   December 11th, 2025