# plot 3D fun in x, y and z

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hend on 28 Mar 2017
Commented: KSSV on 30 Mar 2017
i want to draw a function f varied in x, y and z such that f = xyz using matlab 2014a

John BG on 28 Mar 2017
Hi hend
since your function takes in all 3 coordinates, the only way to 'see' or plot the function is slicing the volume comprised by the domain used.
For such purpose the command slice comes really handy, have a look:
N=10
range=[-N:1:N]
[x,y,z] = meshgrid(range,range,range);
v = x.*y.*z;
figure
colormap hsv
for k = range
hsp = surf(linspace(-N,N,numel(range)),linspace(-N,N,numel(range)), zeros(numel(range)) + k);
rotate(hsp,[2,-2,2],15)
xd = hsp.XData;yd = hsp.YData;zd = hsp.ZData;
delete(hsp)
slice(x,y,z,v,[-N,N],2*N,-2*N) % static volume boundaries
hold on
h1=slice(x,y,z,v,xd,yd,zd) % this is the slicing plane
hold off
view(-5,10)
axis([-10 10 -10 10 -10 10])
drawnow
colorbar
end
note the handle h1 to pull the values on the slice plane, that may be useful to extract the slicing plane points with
Xslice=h1.XData
Yslice=h1.YData
Zslice=h1.ZData
the colour bar is also useful to visualise the actual value of the function.
if you find these lines useful would you please be so kind consider marking my answer as Accepted Answer?
thanks in advance for time and attention
John BG

KSSV on 28 Mar 2017
N = 10 ;
x = linspace(0,1,N) ;
y = linspace(0,1,N) ;
z = linspace(0,1,N) ;
[X,Y,Z] = meshgrid(x,y,z) ;
f = X.*Y.*Z ;
figure(1)
hold on
for i = 1:N
surf(X(:,:,i),Y(:,:,i),Z(:,:,i),f(:,:,i))
end

hend on 28 Mar 2017
thanks for help, but that is not a shape for the desired fn, just levels of coloured blocks as image fn not as a shape
KSSV on 28 Mar 2017
You check the ranges of x, y, z for the given function that's the shape. What you expect? Any image available? Attach it.
KSSV on 30 Mar 2017
N = 10 ;
x = linspace(0,1,N) ;
y = linspace(0,1,N) ;
z = linspace(0,1,N) ;
[X,Y,Z] = meshgrid(x,y,z) ;
F = X.*Y.*Z ;
isosurface(X,Y,Z,F,0)