fit curves by smoothingspline

I have a sets of data, and I want to plot them in dot then fit them with curve, but the fitted curve doesnt seems fit very well(the curve is so far away from realy point. I'm using the code below for fit, did I make some mistake?

clear all
load positiontest.mat
xx;
Pattern3;

curve3 = fit(xx,Pattern3,'smoothingspline');
figure,
plot(curve3,xx,Pattern2)

Answer 1

[Matt J]

Shouldn't this be,

plot(curve3,xx,Pattern3)

[yizheng li]

thanks , I just notice thie typo. But even though I fix it, the first half of this graph still seems not fit well

[Matt J]

You might have to experiment with the SmoothingParam input parameter, e.g.

f = fit(xx,Pattern3,'smoothingspline','SmoothingParam',0.07);