Matt Graham

Is this not the case now?

Shoot...I'll fix this.

Here is where CKFProcessor gets the field and gives it to ACTS (via the Stepper). https://github.com/LDMX-Software/ldmx-sw/blob/ea2a21c94057cf6eba09ce2b75f555976f6097df/Tracking/src/Tracking/Reco/CKFProcessor.cxx#L118 ...loads it in from the text file. I'm a bit surprised the stepper doesn't...

The InterpolatedMagneticField3 is defined here: https://github.com/LDMX-Software/ldmx-sw/blob/ea2a21c94057cf6eba09ce2b75f555976f6097df/Tracking/include/Tracking/Sim/BFieldXYZUtils.h#L18 `using InterpolatedMagneticField3 = Acts::InterpolatedBFieldMap< Acts::Grid>;` So, we sort of control it, but not the base "InterpolatedBFieldMap". One thing we might be able to do...

> Interesting this didnt seem to have solved the issue > > in https://github.com/LDMX-Software/ldmx-sw/actions/runs/14349763985/job/40226890572?pr=1685 > > ``` > < 22:35:18 PROP ERROR Step failed with MagneticFieldError:1: Interpolation out of bounds...

> > Interesting this didnt seem to have solved the issue > > in https://github.com/LDMX-Software/ldmx-sw/actions/runs/14349763985/job/40226890572?pr=1685 > > ``` > > < 22:35:18 PROP ERROR Step failed with MagneticFieldError:1: Interpolation out...

> Non of the distributions change tho, are we sure that this part of the code is not overwritten somehow later on from the GMDL maybe @bloodyyugo ? I thought...

Yeah, ParticleHypothesis takes the absolute value of the pdgid. In you can just delete this line in TruthSeedProcessor: [https://github.com/LDMX-Software/ldmx-sw/blob/25e45c03a85d33f73823c7eb8af89a6e2f39925b/Tracking/src/Tracking/Reco/TruthSeedProcessor.cxx#L146](https://github.com/LDMX-Software/ldmx-sw/blob/25e45c03a85d33f73823c7eb8af89a6e2f39925b/Tracking/src/Tracking/Reco/TruthSeedProcessor.cxx#L146 )

This does not put all of the parameters into detector coordinates. Really, the only thing that changes is the 3-momentum. The helix parameters don't really make any sense to rotate...

You bring up a good point that I've been going back-and-forth with...ACTs (and every other tracking code I've seen) parameterizes the helix using the perigee of the helix wrt a...