Calling markers of arm26 in python

[Gautam Ramachandra]

Hi,
Need help in calling the marker function and getting its coordinates in python , for example when we want to call the joint coordinate we use this

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self.osim_model.joints[0].getCoordinate(0).getValue(self.osim_model.state)

likewise how to get the x,y,z for the marker that is attached to the arm model on the wrist ?

[jimmy d]

Are you using the 3.3 or 4.0 API?

In 3.3 (Matlab, you can make the Python changes)

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model = Model('path2model.osim');
s = model.initSystem();

% get a reference to a marker (0 index)
m = modelgetMarkerSet().get(0);
b = m.getBody();
% get marker offset on the body
p_l = m.getOffset();

% Use the Simbody Engine to compute location in ground
sbe = model.getSimbodyEngine();
% Define an empty vec3 to put the posiion data into
p_g = Vec3()
% get the position
sbe.getPosition(s, b, p_l, p_g);

in 4.0

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p_g = model.getMarkerSet().get(0).getLocationInGround(s);

[Gautam Ramachandra]

Thank you for the reply, I use 4.0 and used this

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 self.osim_model.model.getBodySet().get("r_ulna_radius_hand") 

but as the hand moves the coordinate are not changing it is repeating the same coordinate

and if I use this

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p_g = model.getMarkerSet().get(0).getLocationInGround(s);

by default it will take the shoulder marker but I need to call the marker found on the wrist

[jimmy d]

but as the hand moves the coordinate are not changing it is repeating the same coordinate

I am not sure how to interpret that. How do you know the hand is moving? When are you doing this analysis? Shouldn't you be setting the value of the coordinate using setValue()

by default it will take the shoulder marker but I need to call the marker found on the wrist

Did you bother to change the index value in .get()?

[Gautam Ramachandra]

Thanks I got it, had made a mistake in my program, my objective function was not right.