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The .osimx File Type

Because model properties that are not described in OpenSim model files (.osim) are optimized and used across the NMSM Pipeline, an addendum file of the type .osimx is saved and passed between tools. The specifics of these files are discussed here.

Muscle Properties

The following elements can be included in the muscle properties of the .osimx XML file:

  • <electromechanical_delay>
  • <activation_time_constant>
  • <activation_nonlinearity_constant>
  • <emg_scale_factor>
  • <optimal_fiber_length>
  • <tendon_slack_length>
  • <max_isometric_force>

Ground Contact Properties

The .osimx file also includes ground contact properties that can be used to inform Treatment Optimization.

Contact surface elements contain information about the GCP results to full describe the personalization:

  • <resting_spring_length>
  • <dynamic_friction_coefficient>
  • <viscous_friction_coefficient>
  • <damping_factor>
  • <latching_velocity>