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Old 06-30-2009, 04:30 AM
bharatbhushan bharatbhushan is offline
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Join Date: Jan 2009
Location: Mumbai
Posts: 3
problem in setting the orientation of bones

hi...
I am using XBAS master from XSENS for animating the avatar. I have placed 3 MTx sensors on thorax, Upper arm and Scapula(not considering the forearm sensor as as of now, shown in the last attachment ). I have determined the relative orientation of each sensor to its segment. I am using this relative orientation to calculate the segment's orientation from sensor's orientation. I have also determined the relative orientation of upper arm and scapula with respect to thorax both in Euler and rotation matrix form.

I am facing Following problems:

1) what can be used for scapula?

2) how to use link command to animate the avatar in real time. Direct linking to sensor will use sensor orientation in global coordinates while I want to use relative segment orientation for ex. upper arm segment orientation w.r.t. thorax.

3) In non real time mode I have saved the relative orientation of upper arm and scapula with respect to thorax in rotation matrix format and imported them in Vizard. I am using these values with a timer. I have used the rotation matrix format to avoid any errors caused by the order of rotation(as I believe Vizard and XSENS uses different order of rotation). The problem is when I import the avatar file it's hands are rotated outside in its initial state, but the action performed by my subject starts in standard anatomical position. How to adjust this? also the coordinate system used by Vizard is different than that of XSENS and the defined coordinates of the segments(given in the attachment). so what transformations(for adjusting the hands and for axes mismatch) must be used before using <bone>.setmatrix command.

I have tried to do all of these with different commands but still not able to get the correct code so please help me out here.

thanx and regards--
bharat

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