Query using contact surfaces

[Vishal R]

Hi,

I have been doing CMC on 2392 lower extremity model for normal level ground walking. I have been doing the analysis with GRF data from the force platforms. I also did CMC without external loads. Then, upon comparison of the muscle excitations there are huge differences between them. The CMC results with GRF had similar patterns to the EMG data collected during the experimentation.

Now my question:
Can we use the contact surfaces (spheres) on the foot and make the platform as ContactHalfSpace and along with that, using the ForceReporter in forward dynamic to calculate the ground reaction forces acting on the model. So that, by using just the motion capture data and the GRF data from ForceReporter tool, could we get the similar results produced using external loads information from force platform during the experimentation while executing CMC?

The main intention of this question is to ask, whether the analysis like RRA/CMC/SO could be done if we do not have GRF data from force platforms. This complicated idea was because of this question.

Thanks,
Vishal

[jimmy d]

Can we use the contact surfaces (spheres) on the foot and make the platform as ContactHalfSpace and along with that, using the ForceReporter in forward dynamic to calculate the ground reaction forces acting on the model.

Sure. People have tried it before and I am pretty sure there are published works out there (Don't think it was OpenSim though, maybe Anybody?).

could we get the similar results

Ball park? maybe. Accurate? doubt it. Depends on what your research question is and how fine grain you need to be.