DD4hep Meeting August 28th, 2025

Present:    Markus, Thomas

Apologies: Andre

Link to minutes of previous meeting

Merged PRs

• PR1488:        Use helicity for MCParticle when available (Thomas)
    ---> Enhancement to propagate generator information

Closed PRs, closed issues and fixed problems

• ------

Pending Problems

• ISSUE1285:  Memory Consumption of Sensitive Detectors
                        ==> Should be handled as illustrated in PR1288. Intrinsic problem of the Geant4VolumeManager;
• ISSUE1297:  Possible to dump all available readout elements?
                        ==> Possibly a copy of unsolved ISSUE580 from Valentin about enumerating all sensitive cells.
• ISSUE1319:  Problem with regexSensitiveDetector and volume IDs
                        ==> Interesting use case for reg-ex sensitive detectors
                               having a VolumeMgr equivalent.
• 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.
• PR1240:        Add multithreading support to ddsim
• PR1314:        Cylinder segment surface (Armin Ilg)
• 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
• ISSUE1469: Memory leak in Compact2Objects / Detector concerning Headerbug
    ---> See MR #1478
• ISSUE1487: The test t_DDDigi_sim_test_weighted_deposit_overlay can fail (Juan)
    ---> Unstable test
  
  New:
• ISSUE1489:  using SkinSurfacequestion
• ISSUE1490:  Discrepancy in Material Encountered by graphicalScan and g4MaterialScan Commandsbug
                        ---> Required warning about tessellated surfaces
• ISSUE1492:  Readout segmentation for multiple cylinders with offset axesquestion
                        ----> Unclear code in CylindricalGridPhiZ.cpp line 80
                        ----> Try special case where axis is identical to beam axis.
  
  Pending:
• PR1491: Remove an include of a folder that does not exist in ClientTests (Juan)

Round Table

Markus:  NTR
Thomas: NTR

AOB

Next meeting:   September 11th, 2025