SimmSpline data interpolation 100 to 1000Hz

[Erik Dijkstra]

Hi all,

I am trying to spline fit kinematic data to get it with a sample frequency equal to the ground reaction forces (1000Hz) but I am not succeeding very well with this.

I think I successfully managed to create the simmsplines with the following

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SimmSpline rSpline, lSpline;
	for(int i=1; i<MTime.getSize()-1;i++){
		rSpline.addPoint(MTime[i],vRMF[i]);
		lSpline.addPoint(MTime[i],vLMF[i]);
	}

where MTime and vRMF/vLMF are arrays containing the time and velocity values of a point.

From here I thought I could use the function

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double aValue = rSpline.calcValue(x)

to get the spline function values at all the timings of the GRF but this function only takes a constant SimTK::Vector of size 1(this I checked with the 'argumentsize' function). This gave back a insanely large number when I placed a value from the MTime array in the constant SimTK::Vector.

So my question is how does this work with the SimmSpline? All I want is an array or vector with interpolated 'Y' values from the cubic spline fit with a given set of data.

Best regards,
Erik