CM motion data
Submitted by sinisa_s on Tue, 05/12/2009 - 23:24
Dear All,
I wanted to use CM motion data (Segment CM Locations) for driving LifeMod model. Therefore, I made small experiment. For Britney model (walking tutorial) I measured displacement and orientation of the CM markers using built-in requests DAT_Bdisp_Britney_(name of segment). From these data I formed a slf file according to StairClimb.slf (from tutorial; slf file is in attachment). Equilibrium analysis is Ok if I start with full motion data set (not partially; I tried as in Walking tutorial to start form 1,5sec). But when I try to do simulation to record joint motions (angles) I got following errors for some point motions:
ERROR: Initial displacement of MOTION World.Britney_MOTagent_11__U4 differs from that of its I and J markers, by -180.0 degrees.
Do you have some suggestion how to solve this problem? Is it at all possible to use data from above mentioned requests to form slf file (I am not sure do rotations from requests correspond to rotations in slf file).
Does someone have some CG motion files that passes simulation or some additional documentation for CG motion file format?
Best regards,
Sinisa
I wanted to use CM motion data (Segment CM Locations) for driving LifeMod model. Therefore, I made small experiment. For Britney model (walking tutorial) I measured displacement and orientation of the CM markers using built-in requests DAT_Bdisp_Britney_(name of segment). From these data I formed a slf file according to StairClimb.slf (from tutorial; slf file is in attachment). Equilibrium analysis is Ok if I start with full motion data set (not partially; I tried as in Walking tutorial to start form 1,5sec). But when I try to do simulation to record joint motions (angles) I got following errors for some point motions:
ERROR: Initial displacement of MOTION World.Britney_MOTagent_11__U4 differs from that of its I and J markers, by -180.0 degrees.
Do you have some suggestion how to solve this problem? Is it at all possible to use data from above mentioned requests to form slf file (I am not sure do rotations from requests correspond to rotations in slf file).
Does someone have some CG motion files that passes simulation or some additional documentation for CG motion file format?
Best regards,
Sinisa
I think you are correct in g...
1: Rather than using the CM marker set, you could place a few additional markers on each segment (3 is ideal) and then track and enter into an slf only the positions (not rotations) of those markers. Then you would be able to recreate those markers/ positions in another model and go from there. Or, just use one of the other included marker sets (plugin, davis, golfer) which also avoids this angle problem.
2: If you are specifically interested in working with the CM motion data format, Id recommend you start with the StairClimb.slf which it sounds like you've looked at a bit already. Try modifying some of the data in there to see if it behaves in the way you think it should; this might work a bit better than starting with an entirely different data set.
Best of luck with your modeling!