I feel a liitle confused about the model file in a built-in model of OpenSim 4.4 (in folder: ...\Models\Gait10dof18musc). The follows are part of the code in .osim file:
My confusion is that, in definition of knee joint, why 'Location of the joint in the parent body (femur)' and 'Location of the joint in the child body (tibia)' are all [0 0 0]. Seem this is different from the actual condition? Thank you very much if you can help to illustrate!
Code: Select all
<Body name="tibia_r">
<mass>3.7075</mass>
<mass_center> 0 -0.1867 0</mass_center>
<inertia_xx>0.0504</inertia_xx>
<inertia_yy>0.0051</inertia_yy>
<inertia_zz>0.0511</inertia_zz>
<inertia_xy>0</inertia_xy>
<inertia_xz>0</inertia_xz>
<inertia_yz>0</inertia_yz>
<!--Joint that connects this body with the parent body.-->
<Joint>
<CustomJoint name="knee_r">
<!--Name of the parent body to which this joint connects its owner body.-->
<parent_body>femur_r</parent_body>
<!--Location of the joint in the parent body specified in the parent reference frame. Default is (0,0,0).-->
<location_in_parent>0 0 0</location_in_parent>
<!--Orientation of the joint in the parent body specified in the parent reference frame. Euler XYZ body-fixed rotation angles are used to express the orientation. Default is (0,0,0).-->
<orientation_in_parent>0 0 0</orientation_in_parent>
<!--Location of the joint in the child body specified in the child reference frame. For SIMM models, this vector is always the zero vector (i.e., the body reference frame coincides with the joint). -->
<location>0 0 0</location>
<!--Orientation of the joint in the owing body specified in the owning body reference frame. Euler XYZ body-fixed rotation angles are used to express the orientation. -->
<orientation>0 0 0</orientation>
<!--Set holding the generalized coordinates (q's) that parmeterize this joint.-->
<CoordinateSet>