Shaded surface

Hi

I have 3 Arrays with values of which i am doing a 3D plot. Currently i am using "plot3()". I would rather like to have a shaded surface...

        x(i)=[cos(psi)*cos(phi)*r];
        y(i)=[cos(psi)*sin(phi)*r];
        z(i)=[sin(psi)*r];
        plot3(x,y,z)

Any Hints?

Answer 1

[Grzegorz Knor]

St11=100;
Sc11=St11*2/3;
St22=80;
Sc22=St22*2/3;
S=60;

i1 = 0;
r = NaN(101,51);

for phi=0:pi/50:2*pi
    i1 = i1+1;
    i2 = 0;
    if cos(phi)>=0
        X=St11;
    else
        X=Sc11;
    end
    if sin(phi)>=0
        Y=St22;
    else
        Y=Sc22;
    end
    for psi=-pi/2:pi/50:pi/2
        i2=i2+1;
        F=@(r0)(((cos(phi)*cos(psi)*r0)/X)^2-(cos(phi)*cos(psi)*r0*sin(phi)*cos(psi)*r0)/(X^2)+((sin(phi)*cos(psi)*r0)/Y)^2+(r0*sin(psi)/S)^2-1)^2;
        r(i1,i2)=abs(fminsearch(F,0));
    end
end
[psi,phi] = meshgrid(-pi/2:pi/50:pi/2,0:pi/50:2*pi);
x=cos(psi).*cos(phi).*r;
y=cos(psi).*sin(phi).*r;
z=sin(psi).*r;
surf(x,y,z)

Answer 2

[Grzegorz Knor]

[psi phi] = meshgrid(0:0.05:2*pi);
r = 1;
x=cos(psi).*cos(phi).*r;
y=cos(psi).*sin(phi).*r;
z=sin(psi).*r;
surf(x,y,z)
shading interp

By the way, to draw sphere you could use sphere function:

sphere
axis equal

Answer 3

[Ben]

It's not that simple, r is not constant. So I am not plotting a sphere. I'll post the full code, so maybe you can help me...

 St11=100;
 Sc11=St11*2/3;
 St22=80;
 Sc22=St22*2/3;
 S=60;

 for phi=0:pi/50:2*pi

    phi*360/(2*pi);
    if cos(phi)>=0
       X=St11;
    else
       X=Sc11;
    end
    if sin(phi)>=0
       Y=St22;
    else
       Y=Sc22;
    end
    for psi=-pi/2:pi/50:pi/2
        psi*360/(2*pi);
        F=@(r0)(((cos(phi)*cos(psi)*r0)/X)^2-(cos(phi)*cos(psi)*r0*sin(phi)*cos(psi)*r0)/(X^2)+((sin(phi)*cos(psi)*r0)/Y)^2+(r0*sin(psi)/S)^2-1)^2;
        r=abs(fminsearch(F,0));
        i=i+1;
        x(i)=[cos(psi)*cos(phi)*r];
        y(i)=[cos(psi)*sin(phi)*r];
        z(i)=[sin(psi)*r];
    end
 end
 plot3(x,y,z)

The performance of the plot is very bad and not nice to look at. Calculationtime approx. 30 seconds...

[Ben]

AWESOME! ;) thank you for you time!

[Ben]

*your time!