How to use isocolor with you own color condition ?

I'm using a code

interval = [-3:0.1:3];
a= interval ;
b= interval;
c= interval;
[A,B,C] = meshgrid(a,b,c);

data = cos(A) + cos(B) + cos(C);
cdata = smooth3(rand(size(data)),'box',7);
p = patch(isosurface(A,B,C,data,0));
isonormals(A,B,C,data,p)
isocolors(A,B,C,cdata,p)
p.FaceColor = 'interp';
p.EdgeColor = 'none';
view(150,30)
daspect([1 1 1])
axis tight
camlight
lighting gouraud

but now the color grandient is given by random, I would like to give a gradient by k which is the function of coordinate x y z how can I do that

syms x y z 

f = cos(x) + cos(y) + cos(z);

fx = diff(f,x);
fy = diff(f,y);
fz = diff(f,z);

fxx = diff(fx,x);
fxy = diff(fx,y);
fxz = diff(fx,z);

fyx = diff(fy,x);
fyy = diff(fy,y);
fyz = diff(fy,z);

fzx = diff(fz,x);
fzy = diff(fz,y);
fzz = diff(fz,z);

mat = [fxx fxy fxz fx; fyx fyy fyz fy; fzx fzy fzz fz; fx fy fz 0];
no = det(mat);
de = (fx^2 + fy^2 + fz^2)^2;
k = de/no;

Answer 1

[Aghamarsh Varanasi]

Hi,

You can use the 6th argument of ‘isosurface’ to change the color gradient of the isosurface.

Here is an example

[x,y,z,v] = flow; 
[faces,verts,colors] = isosurface(x,y,z,v,-3,x); 
patch('Vertices', verts, 'Faces', faces, ... 
    'FaceVertexCData', colors, ... 
    'FaceColor','interp', ... 
    'edgecolor', 'interp') 
view(3)

Note that as x increases, the color goes from the dark blue to the red.

For reference you can check this example

https://www.mathworks.com/help/matlab/ref/isosurface.html