Why do Modal Analysis results from another program NOT match Modal Analysis results from AutoPIPE?
"The modal displacements and rotations describe the set of natural "shapes" or "patterns" of the system when vibrating (no external load). The model shapes depend on how the system's mass and stiffness are distributed. The displacements and rotations are not absolute. In fact, some programs report the normalized modal displacements relative to the maximum modal displacement. The frequency and participation factor for each mode determines how that mode will contribute to the overall system's response from a dynamic external load. It depends on how close the frequencies of the external load are to the frequencies of the mode shapes.
To duplicate the results of another program, scan the results for the maximum values for each direction and divide all values by the maximum. Use MS Excel to help perform this task, and than compare to AutoPIPE
Again, Normalization to 1 is common, but mass normalization of mode shapes is more common and is used by AutoPIPE..
"Mode Shape" sub report
Bentley AutoPIPE