Hi everyone

So i want to introduce imperfections to my part using the output from my modal analysis.

after doing the modal analysis it is said that one can sum displacement of the x(let's say 8) number of modes using eigenvalues and add them as geometrical imperfections to the analysis. now *PERTURBATION_NODE keyword has a deck of "FNAME,Name of file containing the perturbation definitions." what should i use for this input here? should I make the file?

Thank you for your answers