Hi John,
I'm currently working on getting the same step to work with Vicon's plug-in-gait marker set. The issue seems to be that the headers for angle names and the names of the force plate output. There's really two options:
1) Generate the information that is needed in the .mot file and then cut and paste it into the appropriate sections of the demo files. This would work well if you only have a few trials you need to investigate or will just be doing a couple from time to time.
2) Edit all the .xml files so that the names for angles/forces in the demo files are changed to the corresponding names you're able to generate. I'm currently working on getting this method working for PiG as I have data for a few dozen subjects I want to work with. If you decide to go this route, the easiest way I've found to make sure nothing is missed is to copy and paste all the .xml files in to notepad or similar and use the 'find: replace all' function, then paste the changed documents back in the appropriate file.
Number 2 assumes, of course, that you have something available to export the .mot file and it's working properly. If that's not the case, number 1 is probably your best bet.
Hope this helps,
Dan
MarkerSet
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Daniel Leib
- Posts: 75
- Joined: Mon Sep 11, 2006 6:44 am
RE: MarkerSet
**edit: "The issue seems to be that the headers for angle names and the names of the force plate output don't match what opensim expects"
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Pablo Ortega
- Posts: 28
- Joined: Fri Apr 18, 2008 8:29 pm
RE: MarkerSet
Hi,
I'm trying to do my own .xml marker set but my dubt is where you can see the location of the marker, e.g. LFHD -0.01 0.6 -0.06? how do you define this values?
I'm trying to do my own .xml marker set but my dubt is where you can see the location of the marker, e.g. LFHD -0.01 0.6 -0.06? how do you define this values?
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Ayman Habib
- Posts: 2238
- Joined: Fri Apr 01, 2005 12:24 pm
RE: MarkerSet
Hi Pablo,
Markers are included in the model file (.osim) under the xml tag
<MarkerSet name="">
<objects>
<Marker name="Sternum">
<!--Body segment in the model on which the marker resides.-->
<body> torso </body>
<!--Location of a marker on the body segment.-->
<location> 0.12051001 0.30726367 -0.00324928 </location>
</Marker>
....
</MarkerSet>
As indicated in the xml comment above, the location is relative to a specific body frame.
Good luck,
-Ayman
Markers are included in the model file (.osim) under the xml tag
<MarkerSet name="">
<objects>
<Marker name="Sternum">
<!--Body segment in the model on which the marker resides.-->
<body> torso </body>
<!--Location of a marker on the body segment.-->
<location> 0.12051001 0.30726367 -0.00324928 </location>
</Marker>
....
</MarkerSet>
As indicated in the xml comment above, the location is relative to a specific body frame.
Good luck,
-Ayman
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Daniel Leib
- Posts: 75
- Joined: Mon Sep 11, 2006 6:44 am
RE: MarkerSet
Hi Pablo,
As Dr. Habib said, I think the answer is scattered among a few posts on the forum, but just so you have it in one place:
The locations are relative to the body (OpenSim/modeling term, you might be used to calling them segments) origin. The units are in meters, which is why the numbers look pretty small. So, in the example you have in your post, the expected location of the LFHD marker is -0.01m,0.6m,-0.06m from the origin of the HAT (head-arms-torso) body.
It may take a little bit of trial and error when you're building your own marker set to get everything oriented with respect to body origins, but if you use the other marker sets as examples you should get a pretty good first guess and then adjust from there. You could also use the methods mentioned in the thread on viewing/editing .vtp files to visualize the origin, but it'd probably be quicker/easier to do an educated guess and check method as you won't have to do it more than a couple times.
Remember that OpenSim can adjust the expected/experimental coordinates to better fit as well, so it doesn't need to be absolutely perfect.
Have a good one,
Dan
As Dr. Habib said, I think the answer is scattered among a few posts on the forum, but just so you have it in one place:
The locations are relative to the body (OpenSim/modeling term, you might be used to calling them segments) origin. The units are in meters, which is why the numbers look pretty small. So, in the example you have in your post, the expected location of the LFHD marker is -0.01m,0.6m,-0.06m from the origin of the HAT (head-arms-torso) body.
It may take a little bit of trial and error when you're building your own marker set to get everything oriented with respect to body origins, but if you use the other marker sets as examples you should get a pretty good first guess and then adjust from there. You could also use the methods mentioned in the thread on viewing/editing .vtp files to visualize the origin, but it'd probably be quicker/easier to do an educated guess and check method as you won't have to do it more than a couple times.
Remember that OpenSim can adjust the expected/experimental coordinates to better fit as well, so it doesn't need to be absolutely perfect.
Have a good one,
Dan
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Andrea Morelli
- Posts: 89
- Joined: Thu Jan 24, 2008 1:10 pm
RE: MarkerSet
I'm try to build my marker set for gait analysis done with Davis marker set.
I've a stupid question... the marker for the joint center (for example at the hip - RHJC) is a a virtual marker calculated ?
Thank you
Andrea
I've a stupid question... the marker for the joint center (for example at the hip - RHJC) is a a virtual marker calculated ?
Thank you
Andrea
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Andrea Morelli
- Posts: 89
- Joined: Thu Jan 24, 2008 1:10 pm
RE: MarkerSet
I modify GAIT2392 model and following the workflow about generating a muscle actuated simuloation i created a setup_scale xml file and aand I converted one of my gait test in a tc format. I changed markers name like my gait model so was quite easy for me to understand it.
The scaling procedure is going fine, file format seems correct, but my scaled subject show the trunk flexed forward a little with left and right acromion marker quite distant from the scaled bone (the same for C7). I try to include this markers adding wieght in the optimization and seems work. But there's a quite high RMS total error.
For the Inverse kinematics I've some problem.
I created setup_IK and IK_task file and they seems correct.
I converted my walking file in the same manner than the static one (instead 22 mks in the static I've 20 becuase i didn't use mks on the hell) but the problem is that if i try to load this file Opensim crash immediately without give any message. Anybody can help me please ?
For your info If i load the static file for the IK all is loading correctly. Seems there's some problem handling the walking file.
Thank you
Andrea
The scaling procedure is going fine, file format seems correct, but my scaled subject show the trunk flexed forward a little with left and right acromion marker quite distant from the scaled bone (the same for C7). I try to include this markers adding wieght in the optimization and seems work. But there's a quite high RMS total error.
For the Inverse kinematics I've some problem.
I created setup_IK and IK_task file and they seems correct.
I converted my walking file in the same manner than the static one (instead 22 mks in the static I've 20 becuase i didn't use mks on the hell) but the problem is that if i try to load this file Opensim crash immediately without give any message. Anybody can help me please ?
For your info If i load the static file for the IK all is loading correctly. Seems there's some problem handling the walking file.
Thank you
Andrea
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Andrea Morelli
- Posts: 89
- Joined: Thu Jan 24, 2008 1:10 pm
RE: MarkerSet
It was an error in creating the file .trc for the movment. I reach to fix it.
Thank you
Andrea
Thank you
Andrea
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Roedolph Opperman
- Posts: 1
- Joined: Fri Dec 14, 2007 2:05 pm
RE: MarkerSet
Hi Dan,
I'm currently running experiments with a Vicon system while using the Helen-Hayes marker set. I had a look at your Plug-in-Gait files and this may be a trival question but could I use this for my Helen-Hayes marker set? If not, could you please give me some advise on how to go about it?
I see that these post are from last year so I am hoping that you have created more marker sets in the mean time.
Thanks much,
Roedolph
I'm currently running experiments with a Vicon system while using the Helen-Hayes marker set. I had a look at your Plug-in-Gait files and this may be a trival question but could I use this for my Helen-Hayes marker set? If not, could you please give me some advise on how to go about it?
I see that these post are from last year so I am hoping that you have created more marker sets in the mean time.
Thanks much,
Roedolph
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Daniel Leib
- Posts: 75
- Joined: Mon Sep 11, 2006 6:44 am
RE: MarkerSet
Hi Roedolph,
You could modify the marker set pretty easily if you want to use it with a standard Helen-Hayes marker set. All you'd need to do is change the names of the markers to match if you're using two posterior pelvic markers (either in your motion capture software or in the xml file) and/or take out the references to the PSIS markers and put in a sacral marker. To use the other files, such as a scaling setup file, you'd need to edit the xml file to change the names of the markers it is referencing to match as well. If you're not very familiar with how to do this, it might be easier to do it once through the GUI and save the setup files from there.
Have a good one,
Dan
You could modify the marker set pretty easily if you want to use it with a standard Helen-Hayes marker set. All you'd need to do is change the names of the markers to match if you're using two posterior pelvic markers (either in your motion capture software or in the xml file) and/or take out the references to the PSIS markers and put in a sacral marker. To use the other files, such as a scaling setup file, you'd need to edit the xml file to change the names of the markers it is referencing to match as well. If you're not very familiar with how to do this, it might be easier to do it once through the GUI and save the setup files from there.
Have a good one,
Dan