Scaling generic model

[Nahime Al Abiad]

Hello
I am trying to scale a generic model to fit some patients data. I have the trc file.
However, the scaling gives a high error(5cm) and RMS. It is complicated to know from where the problem is
for example how do I know if the patient has a bigger pelvis or that the marker's position is simply different from generic model?
Do I move the markers on the generic model and keep trying until the error is small? and how do I make sure that the marker position even though the error is small is right?
I am sorry I am a little confused. Can anyone explain me the process of reducing the error during scaling please?
Should I keep trying to change the marker position on the generic model to finally achieve a small error. Is that the right way?

[Nahime Al Abiad]

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For example here how do I know whether the pelvis is small or the markers are a little misplaced on the patients body.
Same goes for the shoulders. are they bigger or the markers on patient are not the same as the generic model?
and in case the markers on generic model are in different position than on the patients, do I change the positions of markers on generic model manually until it is okay. or is there a faster way ?

[jimmy d]

For example here how do I know whether the pelvis is small or the markers are a little misplaced on the patients body.

You don't know unless you capture some other data to help inform you, like photographs or manual measurements. What we typically recommend is that you take some photos of the subject during the static pose that can help you make that determination. If you don't have photos, you will have to use your own judgement as to the quality.

In case the markers on generic model are in different position than on the patients, do I change the positions of markers on generic model manually until it is okay. or is there a faster way ?

If the markers are used to scale, then yes. However, it will be very difficult for you to make that judgement unless you have some additional information (photos or manual measurements) since you have no perfect reference.

Some material that may help you can be found here and here.