MarkerPlacer Processing Error in Scale Tool

[Nathan Brantly]

Hi OpenSim team,

I am running into this error below anytime I try to execute the MarkerPlacer tool in the MATLAB API scripting environment. The ModelScaler has worked fine for me every time.

Java exception occurred:
java.lang.RuntimeException: SimTK Exception thrown at GCVSPLUtil.h:81:
Bad call to Simbody API method GCVSPLUtil::gcvspl(): Too few data points
(Required condition 'n >= 2*m' was not met.)

at org.opensim.modeling.opensimModelJNI.MarkerPlacer_processModel__SWIG_0(Native
Method)

at org.opensim.modeling.MarkerPlacer.processModel(MarkerPlacer.java:73)

I have run both the ModelScaler and MarkerPlacer in MATLAB for Tutorial 3 (with modifications to runTutorialThree.py) without any issues.

The main difference is that I am now attaching a coordinate MOT file containing the joint angles of the static pose (calculated for a single frame), and I am using the folder organization from the MOtoNMS tool. At first, I thought that this was an issue with the file paths that I was setting in the scaleTool, but I have tried numerous variations on this with no success.

If anyone can help shed some light on what 'n' and 'm' are referring to exactly, I would really appreciate it.

Thank you for your help.

[Nathan Brantly]

Hi again OpenSim Team,

Here is an update to my previous post regarding my problem with running the ScaleTool MarkerPlacer processModel method with an input coordinate MOT file specified.

I have attached my most recently tested MOT file, out.log file, as well as my input XML files.

For now, I will work around this issue by setting all of the IKCoordinateTasks to ‘manual_value’ and looping through. However, it would be much more elegant if I could figure out how to use the MarkerPlacer with an input coordinate MOT file.

Here are my observations based on my testing:

• The MarkerPlacer runs successfully when there are no ‘from_file’ IKCoordinateTasks (i.e. only ‘manual_value’ ValueType properties) in the IKTaskSet and there is no specified coordinate MOT file. The MarkerPlacer does not run successfully when a coordinate MOT file is specified (even when it isn't being used). This seems to indicate that there may be a bug related to including a coordinate MOT file in the MarkerPlacer.
• The out.log file states that an ‘old format’ file is detected. It also says that it is assuming the angles are in degrees even though all angles in the file are written in radians.
• I have tried running the ScaleTool in the GUI with a coordinate file attached. The tool runs indefinitely until I cancel the operation. I have left it running for as long as 45 minutes.
• I have tried numerous changes to my input MOT file, including removing formatting white space except tabs between entries and writing all angles in radians rather than degrees. However, the originally formatted MOT file was correctly read in the GUI when attached to a model.

Please let me know if there is any additional information that I can provide to help in solving this problem.

Thanks,
Nathan

[jimmy d]

Thanks for investigating this bug and giving details about how to reproduce.

I have filed the bug here. Feel free to add information or track.