Modal Analysis discontinuity

[murilloabs]

When performing modal analysis the results obtained have some discontinuity in the mode shape, as shown in the figure below:

This phenomena happend in several models and with other people as @Raimundovpn and @leonardocabr.

[raphaeltimbo]

Thanks for reporting this, @murilloabs! And thanks @Raimundovpn and @leonardocabr for confirming it happens across multiple models.

To investigate, I think we should start by reproducing this with a model already available in tests/data/ (e.g., compressor_example) so we have a reproducible baseline without needing external files.

We should also make sure we have test coverage for all mode shape cases:

• x direction
• y direction
• minor axis
• major axis

That way we can catch discontinuities systematically and prevent regressions once the fix is in place.