I have a program I'm using to compare marker position over time, but I need to add some virtual markers to it to complete my analysis. This might be a dumb question, but is there anyway to re-calculate the trace with virtual markers and export those results? There's plenty of options for saving .mots and whatnot, but I haven't found a way to do traces - I don't want joint angles, I want marker positions. I feel like I'm missing something obvious...
Any help is appreciated. Thanks!
Adding New Markers to a .trc
- Thomas Uchida
- Posts: 1792
- Joined: Wed May 16, 2012 11:40 am
Re: Adding New Markers to a .trc
Not sure what you mean by "trace", but the IK Tool can output marker trajectories over time; see viewtopicPhpbb.php?f=91&t=8311.
- Aaron Godfrey
- Posts: 55
- Joined: Tue Feb 16, 2016 12:34 pm
Re: Adding New Markers to a .trc
I was referring to a .trc file, which is what I use to run IK.
The tool option you pointed out might work, though. Thanks!
The tool option you pointed out might work, though. Thanks!
- Aaron Godfrey
- Posts: 55
- Joined: Tue Feb 16, 2016 12:34 pm
Re: Adding New Markers to a .trc
Having looked into this a little more, it isn't the solution I was looking for. While it does put out an STO of marker locations, it does not put out the location of the virtual markers (i.e., markers that I add to the model prior to running IK, that are tied to various bodies - for example, I'm adding a new marker at the elbow and attaching it to the humerus). Is there a way I can get the output of the marker motion for that new marker?
- Thomas Uchida
- Posts: 1792
- Joined: Wed May 16, 2012 11:40 am
Re: Adding New Markers to a .trc
I haven't dug into the code, but perhaps the Tool reports only the markers that are being tracked (i.e., on which the objective function depends). If so, a quick fix might be to add columns for the virtual markers in your TRC file (with junk trajectories) and set their tracking weights to zero.it does not put out the location of the virtual markers (i.e., markers that I add to the model prior to running IK, that are tied to various bodies - for example, I'm adding a new marker at the elbow and attaching it to the humerus). Is there a way I can get the output of the marker motion for that new marker?
- Aaron Godfrey
- Posts: 55
- Joined: Tue Feb 16, 2016 12:34 pm
Re: Adding New Markers to a .trc
That did it. Thanks again!
- Thomas Uchida
- Posts: 1792
- Joined: Wed May 16, 2012 11:40 am
Re: Adding New Markers to a .trc
Great; thanks for reporting back. You might also want to investigate the scripting interface (https://simtk-confluence.stanford.edu:8 ... /Scripting), which would be a more elegant and flexible approach.