I recently upgraded both FLUKA and Flair to the latest versions on macOS, and while most things work fine, I have run into a strange and reproducible crash affecting only certain projects.
Flair runs normally and FLUKA executes without issue for most projects. However, when I open one particular file — main_study_tc99m.flair — Flair immediately crashes as soon as I click the Geometry tab, with this error:
A very similar project (main_study_lu177.flair) opens and runs fine at first, but if I orbit or move the geometry view at certain angles, it crashes in the same way.
Both projects were created and ran perfectly under FLUKA 4-4.1 and Flair 3.4 on the same machine.
Additional notes
Python version: 3.12.12 (installed via MacPorts)
Installation method: Official.tgz file from the FLUKA website
The model is moderately complex (many bodies and regions).
No special console output appears before the segmentation fault.
Other Flair projects, including examples and test cases, open and display correctly.
I have reinstalled both FLUKA and Flair (including dependencies) from scratch and verified all required packages (tkinter, Tcl/Tk, etc.).
Could this be related to a rendering or OpenGL issue in flair-geoviewer on macOS, or perhaps something that changed in the new FLUKA/Flair versions affecting complex geometries?
Any advice or debugging suggestions would be greatly appreciated.
The problem lies with the parameter 3D.reflections: 4 in the 3D geometry layer.
Simply remove this line from the Flair file using any editor and it should resolve the issue.
We’re currently investigating the source of this problem.
Thank you for your response. Removing 3d.reflections from the flair file now allows me to open the GeoViewer without Flair crashing. I really appreciate the solution!
As an additional note, even after applying this fix, if I adjust the Quality setting within the 3D layer, the same crash and error output still occur. I thought this might be useful to mention.
the problem comes from an internal configuration issue of a new feature that did not show up on my dev machine. It is only triggered when activating the quality mode by moving the slider at least one notch to the right. As this feature is not active in the std. mode it won’t trigger the crash if the quality setting is the default (quality slider to the most left position).
The source is found and I have implemented a fix that should become available in a respin.
If you allow me, then I would just like to add some general remarks looking at the 3D settings that you apply. In order to have photorealistic quality there is no need to move the slider to the most right position. Moving it already one notch to the right is sufficient for 99% of the cases. If you increase the setting further the number of photon scatterings that the renderer follows up, is increased. However, the visual impact is often very subtle and render times increase exponentially!
You have also set the ambient occlusion slider to the most right position. This will give you the best quality but comes at the cost of runtime. Due to some clever math, moving it to a position of 1/3 or 1/2 of the total range is often already sufficient. You might still see some visual noise but with the new denoiser this can be taken care of in a much quicker but less accurate way. See the following examples:
Unless you are a graphics professional I don’t think you will see a notable difference between the first/second and the third one which takes much more time to compute.
As you can see below with the screenshot, you can already get decent results at much lower rendering times:
Thanks for resolving the issue and for the helpful insights on the 3D settings. I will adjust my configuration accordingly once I re-update Flair with this fix.
