A developer/preview PrePoMax version v1.4.0 has been released

The new release version was prepared to test the new features around the steady state dynamic analysis.


In order to perform such an analysis, several changes must be made since the official windows CalculiX version does not always work for such an analysis type. For that reason another compiled CalculiX version was added to the .zip package, which is compiled by Prool: CalculiX 2.20 for Win64 - CalculiX

First of all, a model with a Frequency step (Storage = Yes) and a Steady state dynamics step must be prepared. Then the default solver must be replaced with the Prools solver:

  • Tools → Settings → Calculix → Executable: …\PrePoMax v1.4.0 dev\Solver\ccx2.20\ccx.exe

Prools CaculiX version must be run in a compatibility mode (for unknown reasons) which is activated by opening the analysis properties:

  • Double click on the analysis name → Compatibility mode: On

And then, the computation should work for most cases. For me, there were also cases where the analysis failed after the computation of the first step. For some reason, it helped to change the mesh density. Or some other model setting.

I decided to work with the harmonic response in terms of magnitude and phase in degrees (from 0° to 360°). In this sense, I added support for imaginary load and displacement components (Load case=2) in terms of phase angles.

I successfully test a rotating load using a 90° phase shift, but I could not successfully test any phase shift to a boundary condition. I tested this also on a Linux os, but it did not work.

The harmonic results can be displayed in the following ways:


  • Real: real component of the harmonic result (coordinate values and invariants)
  • Imaginary: imaginary component of the harmonic result (coordinate values only)
  • Magnitude: amplitude of the harmonic response - the largest values of coordinate result values (coordinate values only)
  • Phase: phase angle in degrees of the harmonic response (coordinate values only)
  • Result at angle: result of the harmonic response defined by an angle (coordinate values and invariants)
  • Max: the maximum result at any angle (invariants only)
  • Angle at max: the angle at which the maximum was found (invariants only)
  • Min: the minimum result at any angle (invariants only)
  • Angle at min: the angle at which the minimum was found (invariants only)

Due to the large intensity of finding the max and min values, a simple loop of all angles from 0° to 360° with a step of 1° is used. So the max/min results are accurate up to an angle of 1°. If you have some idea of how to compute these values accurately, please let me know (the problem with using gradient methods is that some invariants have a response with multiple saddles).

Support for animating the harmonic response was added to the animation pane. In order to be able to activate it, a complex result of type Real must be selected first. Then the animation pane must be opened, the button More clicked, and the Harmonic animation type selected.

Harmonic response can also be created as a history output. A new harmonic history output is created by:

  • Double click on the History Outputs in the results tree → Select a Step id → Select an Incrment id → Harmonic = Yes


A history output with a step of 1° angle is computed.


You’ve probably seen that on the CalculiX forum but just in case - I contacted Guido about that issue with SSD analyses on Windows and he fixed it. The fix will be included in the next release of CalculiX (likely in summer) but it’s already available in Guido’s source code repository and Rafal provided a working build for Windows: Steady state dynamics randomly terminates without error - #43 by rafal.brzegowy - CalculiX

That mingw64 version (the other one shows some new issues) is working as expected and most likely could replace the prool’s version (requiring the compatibility mode) in PrePoMax 1.4.0.

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That is excellent news. I will try the new version from Rafal and report on my findings.


A new version of CalculiX (2.21) is available and several bugs are fixed in it, including the one with SSD analyses.

I have updated the release version of PrePoMax v1.4.0 with the new solver.

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