simtk.org

hello,
i have a simple matlab code which loads the model and makes a free falling.
clear all;
import org.opensim.modeling.*
foot1 = Model('C:\Users\shayan\Desktop\model-20170712T165116Z-001/foot1.osim');
s = foot1.initSystem();
manager = Manager(foot1);
x0 = foot1.updCoordinateSet().get('y');
x0.setDefaultValue(3);
manager.setInitialTime(0);
manager.setFinalTime(.04);
manager.integrate(s);
what i want to do is to change the initial state (in my case y, showing the height). using following lines in the above code seems to do the job:
x0 = foot1.updCoordinateSet().get('y');
x0.setDefaultValue(3);

however, the change happens only in .sto or .mot file. and i want to retrieve (see the value) it through matlab. do the previous two lines change the values for center of mass?if so, why running this line (foot1.calcMassCenterPosition(s)) results in a different value than my default value (which was 3)?
the second question is:how can i get the value of state y from one simulation to use it as starting position for another simulation?
regards
Shayan

You can set the default value of the Coordinate, as you are doing, but you would need to call setDefaultValue() before calling initSystem(). However, to specify initial conditions for a simulation, I recommend setting the value of the Coordinate once the State has been created. Here's a simple example (MATLAB, OpenSim 3.3):