How to creat a surface and contours from 3D lines data (x,y,z)

 Hello i've generated this code to creat the borderlines and center line of a vertical curve road. Basicly i want to creat the contours through the road so as far as i understand i have to creat first the surface of the road. I am not very familiar with the plots of matlab so if anyone have any ideas to creat the surface and or the contours of the road would be really healpfull. A perfect senario would be someone to reveal me how i can transfer the hole project in an autocad drawing.
%MILEAGE start position of the road
 XB1=0;
%road wide
bl=20;
%longitudinal to the road slopes
s1=0.02;
s2=-0.02;
%vertical to the road slope
e=0.025;
%Height of start position of the road
HB1=10;
%Radius of the curve of the road
Hw=3000;
%Tangent length
T=(Hw/2)*(s1-s2);
%2*T=Total  milage curve length
% milage end of the road
XB2=XB1+2*T;
%rates of quadratic parabola
a=(s1-s2)/(2*(XB1-XB2));
b=s2-2*a*XB2;
g=HB1-a*XB1^2-b*XB1;
%Quadratic parabola
H= @(x) a*x^2+b*x+g;
i=0;
L=zeros(((2*T)/0.1),3);
for x = XB1 : 0.1 : XB2
    i=i+1;
    %L(i,x,y,z)=[x,y,z of center line of the road]
    L(i,:)=[XB1+x,0,H(x)];
end
% X Y Z Center line of the road
x=L(:,1);
y=L(:,2);
z=L(:,3);
% Υ Ζ Right Borderline
yr=y+(bl/2); 
zr=z+((bl/2)*e);
% Υ Ζ Left Borderline
yl=y-(bl/2);
zl=z-((bl/2)*e);
hold on
%plots center line left borderline and right borderline
plot3(x,y,z)
plot3(x,yl,zl)
plot3(x,yr,zr)