good point ... If you set height and low limit to 0.00 in FreeCAD solver no limit is written to CalculiX which should give all modes requested in count pref ...mac_the_bike wrote: ↑Wed Jul 20, 2022 10:13 amYes but did you ask for negative values? Calculix will always return what you request, provided it is possible, e.g. it can't return modes less than 10Hz if there aren't any. It doesn't return what you don't request, e.g. if you don't request negative eigenvalues then it doesn't return them.For me Calculix does not return any negative value for a cube ... See attached picture. May be the first one, which is even omitted by CalculiX itself.
Also, MAYBE is not really good enough is it? You need unequivocal evidence that it is.
It is interesting to see that the first mode that is output, 0.291E-02, has a label of "Mode 2", but the first mode in the 'PARTICIPATION FACTORS' is 1.
inp file ...
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** At least one step is needed to run an CalculiX analysis of FreeCAD
*STEP
*FREQUENCY
15
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E I G E N V A L U E O U T P U T
MODE NO EIGENVALUE FREQUENCY
REAL PART IMAGINARY PART
(RAD/TIME) (CYCLES/TIME (RAD/TIME)
1 -0.1298234E-02 0.0000000E+00 0.0000000E+00 0.3603102E-01
2 -0.1148171E-03 0.0000000E+00 0.0000000E+00 0.1071527E-01
3 0.5007874E-03 0.2237828E-01 0.3561614E-02 0.0000000E+00
4 0.1390500E-02 0.3728941E-01 0.5934794E-02 0.0000000E+00
5 0.2882176E-02 0.5368590E-01 0.8544376E-02 0.0000000E+00
6 0.3887564E-02 0.6235033E-01 0.9923364E-02 0.0000000E+00
7 0.8379889E+12 0.9154173E+06 0.1456932E+06 0.0000000E+00
8 0.8380244E+12 0.9154368E+06 0.1456963E+06 0.0000000E+00