How do I find intersection of a straight line and a surface?

I have a surface generated via 'fit' function and a straight line which intersects the surface, how do i find this intersection?

Thanks

Answer 1

[Matt J]

One way would be to use fzero. If the parametric equations for your line are L(t)=L0+t*D, the t that gives the intersection could be obtained as,

 t_intersection = fzero(@(t) objective(t,L0,D,fitobj), t0)

 function difference=objective(t,L0,D,fitobj)

    L=L0+t*D;
    x=L(1); y=L(2); z=L(3);

    difference = z-fitobj(x,y);

 end