If you want to get points from a spline curve - I would suggest using ppval
x = 1:10;
y = cos(x);
pp = spline(x,y);
valY = ppval(pp,1)
If you want the piecewise equations, unmkpp will help you out:
[breaks,coefs,l,k,d] = unmkpp(pp)
This is assuming you are using spline in core MALTAB. Let me know if you are using another spline method (in a toolbox).
