DD4hep Meeting September 17th, 2026

Present:     Andre, Juan

Apologies: Markus

Link to minutes of previous meeting

Merged PRs

• PR1663: Geant4Output2EDM4hep: get run from worker context (Andre)

          ISSUE1660: OutputAction and contexts bug (Andre/Thomas)
• PR1666:   Modified FCC MDI Synchrotron Radiation Mask geometry (Who is neskongarr?)
• PR1668: DDG4: catch primaries outside the world volume
• PR1670: fix(Geant4UIManager): do not skip BeamOn when PreRunCommands are set
• PR1674: ClientTests: add references for pseudotrap on gcc16
• PR1675: EventSeeder Remove superfluous call the event seed double seed
• PR1673: fix: rename RETURN template type to avoid macro clash on macOS-15
• PR1669: fix(EventSeed): do not leak the run number from EventParameters between events

Closed PRs, closed issues and fixed problems

• ISSUE1635: ddsim crashes when given a particle outside world volumebug (Andre)
•  

Pending Problems

• ISSUE1335: Uniform random picking of points on detector surfaces for noise studies
                         This problem is linked to #1297 and #580.
• ISSUE1458: Possible discrepancy between xml file and geometry converted into root file
• ISSUE1501: Bug/Feature: Condense duplicated particle contributions in calorimeter question
• ISSUE1568: Sim hits between two sensitive volumes (Alexander Tuna)
• ISSUE1633: Decouple DD4hep Readers/Writers into Separate Source and Injection/Build Stagesenhancement (Simon Gardner)
• ISSUE1643: Non-determinism in hit ordering when multiple detectors share readoutbug (Wouter)

Pending PR:

• PR1606:   feat: AdePT physics list plugin for e+/e-/gamma offload to GPU [WIP] (Wouter)

• PR1626:   feat: add support for python geometry plugins (Wouter)
• PR1658:   [DRAFT POC] Add Arrow IPC stream writer for EDM4hep output (Wouter)
          ---> What is arrow IPC
• PR1664:   feat: honor DD4HEP_LIBRARY_PATH for plugin search (Wouter)
          ---> MacOS is non-trivial!

New:

• ISSUE1657:  DDG4 reduces the generator status to 16 bits and gives no warning (Marco Meyer-Conde)

Round Table

Andre:            New tag 1.38
Juan:              NTR

Next meeting:   October 1st, 2026