Model Measurements

[Daniella Bianchi]

Hello,

I am attempting to compute the scale factors for my model but am unable to locate the length of body parts used in the model gait2354 (or any model for that matter). I thought the scale factor is computed using s = e/m and I have the e values but not the m values. Please help me locate the relevant measurements!

[Thomas Uchida]

One strategy that might be relatively easy would be to place markers on the model at the ends of each segment (or wherever you have measurements), compute the distances between these pairs of markers, compute manual scale factors using your measurements, and enter these scale factors into the Scale Tool.

[Daniella Bianchi]

This is all relatively new to me and does not make much sense.

If you place markers on the model and compute the distances between the pairs of markers using the x,y,z coordinates (are these in metres?), you do not get a uniformly distributed scaling factor. Instead there is a large disparity between the scaling factors i.e. If I computed model markers to be (-0.21, -0.02, 0.065) and my corresponding experimental data to read (-0.056695, -0.0582498, 0.4783) then the scaling factor (e/m) would be (2.714, 29, 7.36) which is very different and large and confusing?

I think it would be worthwhile to upload a video of an example scaling process from scratch in computing the scale factors if possible?

[John Davis]

You might find this webinar useful: https://www.youtube.com/watch?v=ZG7wzvQC6eU
It helped clear up a lot of my confusion about how the scale tool works, and how scale factors are computed.