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% Set the angles of the coordinates (rad).  In Arm26, there are 2 coords:
q=[0 0];

% Load Library
import org.opensim.modeling.*;

% Open a Model by name
osimModelName='arm26.osim';
osimModel = Model(osimModelName);

% Initialize the system and get the initial state
osimState = osimModel.initSystem();

% Get the number of coords and markers
nCoords=osimModel.getCoordinateSet().getSize();
nMarkers=osimModel.getMarkerSet().getSize();

%Get all of the names of the markers
for i=0:nMarkers-1;
    markerNames{i+1}=char(osimModel.getMarkerSet.get(i));
end

%Loop through the coords and set values
for i=1:nCoords
    osimModel.getCoordinateSet().get(i-1).setValue(osimState,q(i));
end

%Realize the model
osimModel.equilibrateMuscles(osimState)

%Get the simbody engine
simbodyEngine = osimModel.getSimbodyEngine();

%Get the ground body
groundBody=simbodyEngine.getGroundBody();

pout=Vec3;  %Make a dummy vector for updating

%Now loop through all of the markers and get their location
for k=0:nMarkers-1
    marker=osimModel.getMarkerSet().get(k);  %Get marker
    mpos=marker.getOffset();                    %Get offset
    body=osimModel.getBodySet().get(marker.getBodyName());  %Get the body
    %Let Simbody do the hardwork
    simbodyEngine.transformPosition(osimState,body,mpos,groundBody,pout) 
    
    %Write to a matrix where each row is a marker 
    markerLoc(k+1,1)=pout.get(0);
    markerLoc(k+1,2)=pout.get(1);
    markerLoc(k+1,3)=pout.get(2);
end

Code: Select all

q = zeros(1, nCoords);