MPCO file not generated properly (0 bytes) even though analysis runs successfully

[qkrghdrl7759]

Hello,

I am working on a structural model in STKO and trying to perform an Eigen Analysis with an MPCO Recorder to visualize the modal shapes in the Post-Processor.

The analysis itself runs successfully (message: ANALYSIS SUCCESSFULLY FINISHED), and the file Results.mpco.cdata is created. However, the actual Results.mpco file is also generated but remains 0 bytes, so nothing can be opened in the Post-Processor.

What I did:

Added an MPCO Recorder in the Analysis Steps, placed before the Eigen step.

Gave a proper name (e.g., Results).

Checked Nodal results → displacement and modesOfVibration.

Also tried adding Element results (force, deformation, localForce).

Ran Write Input File and then executed main.tcl with OpenSees (3.7.1 64-bit).

The analysis runs without any error, but the .mpco database remains empty (0 bytes).

What I expected:

Both Results.mpco and Results.mpco.cdata files with actual results that can be opened in the Post-Processor.

Has anyone experienced this behavior? Could it be related to my recorder configuration or file path issues?

I have attached my full project folder (scd + tcl files) for reference.

Thank you very much for your help.

Best regards,
Hongki Park

[STKO Team]

In OpenSees, the eigen analysis does not automatically records.
So you either do a static or transient analysis after the eigen, or manually call "record" as in this example:

CelMa.zip

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