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Hello, I'm trying to use Open Knee to run on my computer, but I can't get the tf_joint_FEBio_V2.feb to finish the simulation.

Since I couldn't get the files to read in the first place, I have gotten rid of the line <pressure_stiffness>0</pressurestiffness>, and have changed the Module type from solid to solid_old.
After making these changes, I have been able to get the simulation to run, but I haven't been able to get the simulation to run passed 19% (0.34 sec).

Thinking that it may have been an OS compatibility issue, I have changed computers and tried the same, but I have only achieved the same results.
The two computers' specs are as follows:
Workstation 1:
CPU Intel Xeon E3 1225 V2
OS Windows 7 Professional 64bit
RAM 16GB

Workstation 2:
CPU Intel Core i7 4770
OS Windows 8.1 Pro
RAM: 8GB

Should I be changing OS, or have I made an unnecessary change in the feb file?

Dear Kazuki,

We ran the tf_joint_FEBio_V2.feb file to completion a while back using FEBio version v2.1.2.6432. Did you try to use this specific version fo FEBio, at least v2.1? FEBio team regularly updates the version and in some cases this causes convergence issues in models that have been running with previous versions.

Best,

Ahmet

Thank you for your advice.
After your reply, I have run the simulation in several different conditions to figure out the optimal combination of the OS and FEBio version.

Computers which ran the simulations have changed, and RAM has become uniform across platforms at 8 GB.
Conditions are as follows:
OS : Windows 7, Windows 10, Ubuntu 18.04
FEBio : 2.1.0, 2.2.6, 2.7.0

Since listing the results here would become a mess, I have attached an excel file containing the results.
note : Windows 10 + FEBio 2.7.0 & Ubuntu 18.04 + FEBio 2.7.0 haven't finished running the simulations at the point of posting, so results will be updated.

While running these simulations, two things came to my mind.

First, although I think that conditions are as uniform as possible across platforms, was it correct to use the same tf_joint_FEBio_v2.feb file across platforms and versions when I needed to apply different modifications to the code to run the simulations?

Second, considering the fact that the .feb file used for the simulations were developed to be compatible with somewhere around FEBio ver 2.1, should I be developing future tests on Preview2 and running them on whatever condition works best (Ubuntu 18.04 + FEBio ver 2.2.6), or are .feb files generated by the latest version of Preview2 compatible with the latest version of FEBio?

Best,

Kazuki Takahashi

hello Kazuki,

Thank you for the detailed analysis.
1. In my experience the same feb file should run on either platforms using the same febio version.
2. Yes, I would recommend using the most current versions of Preview (2.0) and FEBio. I have had difficulties opening .feb files in preview and .xplt files in postview when using linux (versions have not been updated yet). They all work fine on windows 10.
3. Here's the most up to date version of the model compatible with febio v2.7 https://simtk.org/svn/openknee/_gen1/sr ... o_v2p7.feb . This runs on both windows and linux and the model and results can be opened in Preview and Postview on windows.

Best,
Snehal