just release notes

Author: maureeungaro

releases/0.4.md

@@ -4,6 +4,8 @@ This version includes:
 
 - Field query options to print configured magnetic-field values at absolute coordinates.
 - A `-global_field=<name>` option to attach a configured field to the ROOT world volume.
+- Field-line visualization now derives the sampling extent from the configured ROOT `G4Box` before
+  adding Geant4's magnetic-field model.
 - A `-log_every=N[-NTH]` option for periodic per-event progress logging with the running average rate.
 - A `-print_summary` switch (on by default) that prints total and post-`beamOn` wall-clock time and
   the average event rate at the end of the run.
@@ -22,6 +24,9 @@ This version includes:
 - Added `-global_field=<name>` to associate a configured field with the ROOT (top-level) world
   volume. The field manager is installed on the world and propagated to all daughters, so it applies
   everywhere a more specific per-volume `emfield` is not set.
+- Field-line visualization now applies `/vis/set/extentForField` from the configured ROOT `G4Box`
+  half-lengths before issuing `/vis/scene/add/magneticField`, avoiding misleading field-line
+  sampling when the scene extent is dominated by detector geometry.
 - Added `-log_every=N` (or `-log_every=N-NTH`) to print a `Starting event n. <k> in thread <tid>`
   line each time a worker thread has processed a multiple of `N` events. `<k>` is that thread's own
   1-based event count (not the global Geant4 event id). Every worker logs by default; the optional
@@ -61,8 +66,7 @@ This version includes:
 
 - [Issue #27](https://github.com/gemc/src/issues/27): check Maui's Visualization presentation to add goodies
 - [Issue #28](https://github.com/gemc/src/issues/28): add buttons to g4display
-- [Issue #31](https://github.com/gemc/src/issues/31): improve field ASCII and add SQLITE factory and
-  apply it to gemc3
+- [Issue #31](https://github.com/gemc/src/issues/31): improve field ASCII and add SQLITE factory and apply it to gemc3
 - [Issue #42](https://github.com/gemc/src/issues/42): output options for digitized and true infos
 - [Issue #57](https://github.com/gemc/src/issues/57): min and max field steps definitions
 - [Issue #59](https://github.com/gemc/src/issues/59): TSGQt plotter see B5 example from presentation
@@ -116,6 +120,9 @@ Both x86_64 and ARM64 platforms are supported.
   installed on the ROOT world volume with propagation to all daughters; per-volume `emfield` labels
   still override it locally. The field options are now also aggregated into `gdetector::defineOptions`
   so the option resolves in every context that builds a detector.
+- The GUI field-line toggle now parses the configured ROOT `G4Box` dimensions and sends
+  `/vis/set/extentForField -dx dx -dy dy -dz dz mm` before adding or refreshing the magnetic-field
+  model. Non-`G4Box` roots keep Geant4's default scene-extent behavior.
 - Added periodic event logging in `GEventAction` driven by the `log_every` option (defined in the
   geventaction module). The option string is parsed once per worker into a log module `N` and an
   optional target thread `NTH`; malformed values (non-positive `N`, or `NTH` outside