Xyz model scaling based on BVH Xsens data

Hello,

we are using the xyz scaling option and CalculateSegmentDimensionsFromBVH.any to scale a model to our own set of collected Xsens data, but obtain unrealistically short trunk, so as shown below:

Looking at the file CalculateSegmentDimensionsFromBVH.any indicates that indeed the trunk height is determined from (approx.) L5 (=Xsens Chest2 node) to C1 (=Xsens Head node) so as calculated in the AnyBody Trunk ModelParameters.any.

There is also a factor (currently 1.08) that pre-multiplies the trunk height, which we could arbitrarily increase, but is there a rationale behind it? Why does segment scaling from Xsens data not work as expected in our case? Should we rather use additional points/trials from Xsens to properly scale the model?

Thank you

Hi Marco,

Sorry for slow reply,

When looking at the image i can see that the BVH stick figure and Skeleton fits well in hip and Sternum area. So as i see it the skeleton does its best to follow the stick-figure from xsens.

You can adjust the factor but it will not solve the problem as i see it, since the models already corresponds well, though not very realistic, but thus seems to be caused by the data.

Best regards
Søren

Hi Søren,
Thanks for the reply. When double-checking the model in the Xsens software, we indeed noticed the same body dis-proportions, so we concluded that perhaps the input body dimensions were not measured accurately enough, causing a bad scaling. We are currently investigating if re-measuring the body dimensions fixes this problem.
Best regards,
Marco