I have limit stop or guide with gap. How Caesar II treat this support condition in modal analysis?

Select an operating load case.

If contact is made with that guide, then CAESAR treats it as a guide with 0 gap.

If contact is not made with that guide, then CAESAR treats it as non-existent.

You must close your gaps and limit the scope of your modal analysis in order to receive credible results, even going so far as to create multiple secondary CAESAR files, with displacements applied from the primary one.