Tibia Translation During Scaling

[Karley Baringer]

Hi everyone!

I've been trying to scale the Rajagopal Full Body model according to motion capture data, but I'm encountering an odd problem. During scaling, the tibias translate down so that they completely absorb the tali, and there is an unnaturally large gap between the femurs and tibias. I'm using OpenSim version 4.1, but updating the model file doesn't affect the output. I've also tried weighting the markers at the knee, but that doesn't help either. Moving the tibia up post-scaling causes all the foot bones to move with it, so the tali stay embedded and the feet hover above the ground.

Has anyone encountered this issue? Any advice for how to solve this would be greatly appreciated!

Thank you,
Karley

[Thomas Uchida]

The bone mesh is just a picture. If the model's bodies and joints are correctly defined after scaling, you could simply adjust the size/position of the bone mesh relative to the origin of the body; otherwise, the issue is not just with the mesh. You can check the location of the parent/child frames for each joint by displaying them in the GUI (see the "Displaying Coordinate Axes for Body and Joint Nodes" section here: https://simtk-confluence.stanford.edu:8 ... c+Commands).