Visualization error with small axes

I think I have found a small bug in visualization:

/vis/scene/add/axes 0 0 0 500 nm

causes the following error:

-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : GeomSolids0002
      issued by : G4GenericPolycone::Create()
Illegal input parameters - head
        R/Z cross section is zero or near zero: -9.99939e-10
*** Fatal Error In Argument *** core dump ***
 **** Track information is not available at this moment
 **** Step information is not available at this moment

-------- EEEE -------- G4Exception-END --------- EEEE -------

*** G4Exception: Aborting execution ***
Abort trap: 6

In fact it seems that anything below 560 nm causes this error. I’m guessing from the G4GenericPolycone that it fails when trying to draw the arrowhead. Moreover it seems that 560 nm is the limit regardless of the world size or the zoom—suggesting it’s a precision issue in UReduciblePolygon::Area().

I think we had this problem once. It was fixed in Geant4 10.6 (or even 10.5). What version of Geant4 are you using?

10.5. I have 10.6 on my machine as well, so I’ll try that next

10.6 works. I tested down to 0.001 fm

Great. Thanks for confirming.