DD4hep Meeting March 5th, 2026

Present:     Andre, Juan, Markus, Peter, Thomas

Apologies: 

Link to minutes of previous meeting

Merged PRs

• PR1577:   fix: consistently use dimensionless G4FieldManager epsilon min/max (Wouter)

• PR1579:   Fix warnings seen with gcc16. (Scott Snider)

• PR1578:   Don't use exceptions to test for the presence of an attribute. (Scott Snider)

• PR1455:   TGeoTrd1 generic surfaces (Armin Ilg)

• PR1576:   Fix typos (Markus)

• PR1574:   ParticleHandler: fix keepParticle logic (Andre)

• PR1572:   replace compact.xsd location (Andre)
            ===> Gave warnings/errors in Xerces if not accessible

• PR1573:    add backward, far det types (Derek Anderson)
            ===> ISSUE1544:Feature: additional DetTypes for backward and far detectorsenhancement

Closed PRs, closed issues and fixed problems

• ISSUE1544:  Feature: additional DetTypes for backward and far detectors - enhancement

Pending Problems

• ISSUE1297:  Possible to dump all available readout elements?
                        ==> Possibly a copy of unsolved ISSUE580 from Valentin about enumerating all sensitive cells.
• ISSUE1335:   Uniform random picking of points on detector surfaces for noise studies
                         This problem is linked to #1297 and #580.
• ISSUE1458: XML file vs TGeoStored geometry in GenFit
• ISSUE1501: Bug/Feature: Condense duplicated particle contributions in calorimeter question
• ISSUE1514: How to convert Geant4TrackID into MCParticle Parent ID
• ISSUE1535: How to add new output variables in Hitsquestion (matclim -> DD4SHip)
                        ===> Debugging ongoing

New issues:

• ISSUE1585:  How to create a constant magnetic field with Box shapequestion (quzhaoyi)
                         ===> Assigned Markus
• ISSUE1588:  Placement of volumes using paramVolume1D.
• ISSUE471:    Re-opened issue:  missing MCParticle for particles scattered back into the calorimeter

Pending PR:

• PR1580:  fix: allow improved G4ParameterisedNavigation for pure 1D translation case (Wouter)
• PR1582:  Set the fast simulation flag and adjust step length for contributions created by fast simulation (Thomas)
                   ===> Please see the extended explanation by Thomas concerning this topic in PR1582.
• PR1583:  Give ParticleHandler functions for dropping particles more appropriate names (Thomas)
  + ISSUE1575:    Geant4UserParticleHandler::keepParticle should rather be dropParticle (Thomas)
• PR1584:  feat: use axis-aligned bounding box to pre-filter MultipoleField calls (Wouter)
  + ISSUE1581:    Axis-aligned bounding box for MultipoleField: interest in upstreaming. enhancement (Wouter)
• PR1586:   Fix some memory leaks (Juan)
• PR1587:   Fields/FieldTypes: performance related cleanups (David Lange)

Round Table

Juan:.             NTR
Markus:         NTR
Peter:             NTR
Andre:            NTR

AOB

Next meeting:   March 19th, 2026