function [theForce] = getQfForceX(x_position)
%It is presumed that QuickField is already started, the problem is opened.
%The plunger is placed in x=0 position


%1. Move the plunger to proper position (x_position)
%2. Calculate the force
%3. Move the plunger back to zero position


qf = actxserver ('QuickField.Application'); %get link to QuickField
pbm = qf.Problems.Item(1);      %get link to the problem
pbm.LoadModel;                  %load model
mdl = pbm.Model;                %get link to the model

%1. Move the plunger to proper position (x_position)
%select the object to move, i.e. "insulation"
%(the plunger core is attached to plunger insulation and would be moved automatically)
theShape = mdl.Shapes.get ('LabeledAs','','','insulation');
%specify the displacement vector
theVector = qf.PointXY(x_position, 0);
%move the selected Shape
theShape.Move('qfShift', theVector);
mdl.Shapes.BuildMesh();         %build mesh in the model
mdl.Save;                       %save model file

%2. Calculate the force
pbm.SolveProblem();             %solve the problem
pbm.AnalyzeResults;             %load results
res = pbm.Result;               %get link to the result
%to calculate the force we should build integration contour
%we build the contour in the field window
theFieldWindow = res.GetFieldWindow(1); %open the field window
theContour = theFieldWindow.Contour;    %get link to the contour
theContour.AddBlock1 ('plunger_core');       %add "plunger" block to contour
%calculate the magnetic force integral
theMagneticForce = res.GetIntegral('qfInt_MaxwellForce', theContour).Value;

%3. Move the plunger back to zero position
theVector = qf.PointXY(-x_position, 0);
theShape.Move('qfShift', theVector);
mdl.Save;

theForce = theMagneticForce.X;  %plunger is moved by the X-component of the force