Flair 3.4-5.4 on macOS: viewport lines move before geometry redraws

Flair
1

Versions

Please provide the used software versions.

FLUKA: 4-5.2
Flair: 3.4-5.4
Operating system: macOS Sequioa 15.7.2

Description

Please describe the issue. In case of reporting a bug, please provide step-by-step instructions for reproducing the error.

Dear FLUKA/Flair team,

I have recently updated my macOS installation to:

FLUKA      : 4-5.2
Flair      : 3.4-5.4
Geoviewer  : 3.4-5.4
Python     : 3.12.14
Tk/Tcl     : 8.6
Platform   : darwin

The installation is now stable and Flair/Geoviewer are working correctly after resolving a separate Bus error: 10 issue.

However, I am still seeing a persistent geometry-view behaviour that appears to match the unresolved issue mentioned in this thread Flair crashes in Geometry tab (macOS) — post #12.

The issue is that, when I move/drag the geometry view, the viewport lines move immediately, but the geometry itself does not follow continuously. Instead, the geometry is redrawn only afterwards, when the movement is stopped.

This is particularly apparent when panning or moving the viewport position. The interaction therefore feels as though the viewport overlay is being updated first and the actual geometry render is catching up afterwards.

On the same machine, with Flair/Geoviewer 3.4-5.2, the geometry followed the mouse smoothly and continuously, so this appears to be a change introduced in the newer versions rather than a general macOS performance limitation.

For completeness, my current Flair diagnostic information is:

version     : 3.4-5.4
geoviewer   : 3.4-5.4 False
revision    : df6929e3
last change : Mon Jun 1 10:23:06 2026 +0200
kleidi      : 1790831107.300
python      : 3.12.14 (main, Aug 14 2026, 23:56:42) [Clang 17.0.0 (clang-1700.0.13.5)]
tk          : 8.6
tcl         : 8.6
numpy       : 2.5.3
pydicom     : 3.0.2
platform    : darwin

There is no Python traceback associated with this issue.

Could you please confirm whether this delayed redraw behaviour is expected in 3.4-5.4, or whether it is a known regression? If there is a configuration option or workaround to restore the continuous redraw behaviour seen in 3.4-5.2, I would be very interested in trying it.

Many thanks for your help.

Best regards,
Samuel

3

Dear Samuel,

Thank you for reporting the issue! We encountered the issue on Linux as well when using Gfortran 16 to compile geoviewer.

You could try to delete inline in front of bool GeometryEngine::applyClip(Ray* ray) in engine.cc and recompile geoviewer.

Or, wait for the next release.

Cheers,
David

4

Dear Dávid,

Thank you for your reply.

I will try and implement the change suggested. If that does not work, I will temporarily downgrade to 3.4-5.2 as that was the last version I had working when I previously used Flair and had absolutely no problems with it.

Kind regards,
Samuel