Adjustment of z axis of 3d plot

I'm ploting a 3d graph of displacement of single degree of freedom system against a loading of sin wave.

First I inputed the function. It has its value in terms of a and b. I calculated a and b as initial conditions were given for the function. The final equation I get is only in form of variables x(time) and y(beta) and zai.

I added a for loop so that I may see affect of zai on the displacement. For different zai values displacement varies very much between positive and negative values. I wanted to squeez z values to smaller values for better visualization. Log scale can not be used because negative displacements are also present. What should I do?

clear
clc
syms w wd x a b zai wbar eq1 eq2 u0 v0 y z xx yy
po=1000;
k=40609481.90;
m=12000;
w=sqrt(k/m);
wbar=y*w;
wd=w*sqrt(1-zai^2);
F(x,y)=exp(-zai*w*x)*(a*cos(wd*x)+b*sin(wd*x))+po/k*1/((1-y^2)^2+(2*zai*y)^2)*((1-y^2)*sin(y*w*x)-(2*zai*y)*cos(y*w*x));
F(0,y);
derivF(x,y)=diff(F(x,y),'x');
%derivF(0,y);
eq1=F(0,y)==0;
eq2=derivF(0,y)==0;
sol=solve([eq1,eq2],[a,b]);
%sol.a;
%sol.b;
avalue=sol.a;
bvalue=sol.b;
G(x,y)=subs(F(x,y),[a,b],[avalue,bvalue]);
%G(x,y);

%double(G(0.003,0.05));

x=0:0.005:2.5;
y=0:0.005:3;

[xx,yy]=meshgrid(x,y);
G=matlabFunction(G);

zai=0:0.01:1;

for n=zai
    z=G(xx,yy,n);
    figure(1),clf(1)
    surface(xx,yy,z)
    axis('square')
    axis('tight', 'manual')
    zlim([-5*10^-4 5*10^-4])
    shading interp
    colormap hsv
    view(3)
    %grid on
    drawnow
end

Answer 1

[KALYAN ACHARJYA]

" I wanted to squeez z values to smaller values for better visualization."

zai=0:0.001:1; %z values to smaller values??
for n=1:length(zai)
    z=G(xx,yy,zai(n));
    figure(1),clf(1)
    surface(xx,yy,z)
    axis('square')
    axis('tight', 'manual')
    zlim([-5*10^-4 5*10^-4])
    shading interp
    colormap hsv
    view(3)
    grid on
    drawnow
end

Hope I understood this question, if not please feel free to point it out.

better visualization.??

Do you have any pictorial sample representation/image?

[Osama Anwar]

z axis values have large extremes (max and min values) for corresponding zai value. I want my z values closer to xy plane so that I can have better visualization of shape. I know this can be done by taking logarithmic scale along z axis but it gives distorted results for negative values.