What Does this error even mean??

[x, y, z]=meshgrid(0.5:0.05:0.5, 0.5:0.05:0.5, 0.5:0.05:0.5);

a=0;

for l=1:length(x)

    for j=1:length(y)
        for k=1:length(z)
            a(l, j, k)=k-sqrt((0.25)-((0.58-(l).^2))-((0.58-(j).^2)));
        end
    end
end
surf(x,z,a)

*Error using surf (line 75)

Z must be a matrix, not a scalar or vector*

Answer 1

[the cyclist]

The way you have defined x y and z, they are each just a single number (i.e. a "scalar").

I think maybe you meant

[x, y, z]=meshgrid(-0.5:0.05:0.5, -0.5:0.05:0.5, -0.5:0.05:0.5);

I still get an error from your code when I make that replacement, but I am not quite sure what you intended. I suggest you give

doc surf

a careful read.

[Firew Biruu]

Dear 'The Cyclist', Thank you for your reply. I actually forgot to put the -signs. I managed to get results correcting it as follows;

[x, y]=meshgrid(-1:0.05:1, -1:0.05:1);

for l=1:length(x) for j=1:length(y) a(l, j)=0.5-sqrt((0.58-((0.35-(l).^2))-((0.35-(j).^2)))); end end

surf(x, y, a)

and also for the 2d mesh,

[x, y]=meshgrid(-1:0.05:1, -1:0.05:1);

for l=1:length(x) for j=1:length(y) a(l, j)=0.5-sqrt((0.58-((0.35-(l).^2))-((0.35-(j).^2)))); end end

plot(x, a) hold on plot(y, a)

What I am actually doing is plotting in 2D and 3D the area covered by an end-effector and the height spanned by the carriage as the arm go up and down in a reprap delta robot (transnational)

I surely can use some help on the inverse kinematics visualization of similar machine on Matlab.

Thank you