How can I write a code for a concentric tube represented by points only?

I want to write a code for a cylindrical tube and a metal strut (see attachment for the shape) represented by points. The code will write the points' position and a bond (link) connecting each point to its neighbour.

See below the example of a rectangular code. I dont know how to write that of cylindrical shape.

clc;

clear;

dL=1;

Nx=5;

Ny=3;

Nz=41;

n = 1;

n_bond_types = 3;

dr_Bond(1) = dL;

dr_Bond(2) = sqrt(2)*dL;

dr_Bond(3) = sqrt(3)*dL;

disp('Atoms Positions');

for i=1:Nx

for j=1:Ny

for k=1:Nz

x(n) = i*dL;

y(n) = j*dL;

z(n) = k*dL;

disp([n, x(n), y(n), z(n)]);

Position(n,1)=n;

Position(n,2)=x(n);

Position(n,3)=y(n);

Position(n,4)=z(n);

n = n+1;

end

end

end

Natoms = n - 1;

disp(['Number of Atoms= ', num2str(Natoms)]);

disp(' ');

nb = 1;

disp('Bonds');

for i=1:Natoms

for j=i+1:Natoms

dx = x(j)- x(i);

dy = y(j)- y(i);

dz = z(j)- z(i);

dr = sqrt(dx^2+dy^2+dz^2);

for k = 1:n_bond_types

if (dr> 0.9999*dr_Bond(k) && dr <1.0000001*dr_Bond(k))

disp([nb, k, i, j]);

nb = nb+1;

end

end

end

end

Nbonds = nb - 1;

disp(['Number of bonds= ', num2str(Nbonds)]);

I will appreciate your kind contributions.

Thank you.

[darova]

Can you explain more? You want to build spiral?

[Adamu Mohammed]

Yeah, something like a spiral but with the shape as shown in the attachment. The attachment only show 1/4 section of the geometry.

Thank you.

[darova]

There is no enough information. Please explain what kind of format it is. Faces? Just points?

[Adamu Mohammed]

Yes, all I need is the points now. When I got the points from matlab it can be transform into a particle (atom) shape with a different software. The file attached is the already tranaformed geometry.

[darova]

Do you have any attempts? What about spiral equations?

[Adamu Mohammed]

Thank you very much, but like I said earlier I am interested in the points (position) and the link between the points.

I have the following code for a rectangular geometry (see attached) but I don't know how to write that of cylindrical shape.

clc;

clear;

dL=1;

Nx=5;

Ny=3;

Nz=41;

n = 1;

n_bond_types = 3;

dr_Bond(1) = dL;

dr_Bond(2) = sqrt(2)*dL;

dr_Bond(3) = sqrt(3)*dL;

disp('Atoms Positions');

for i=1:Nx

for j=1:Ny

for k=1:Nz

x(n) = i*dL;

y(n) = j*dL;

z(n) = k*dL;

disp([n, x(n), y(n), z(n)]);

Position(n,1)=n;

Position(n,2)=x(n);

Position(n,3)=y(n);

Position(n,4)=z(n);

n = n+1;

end

end

end

Natoms = n - 1;

disp(['Number of Atoms= ', num2str(Natoms)]);

disp(' ');

nb = 1;

disp('Bonds');

for i=1:Natoms

for j=i+1:Natoms

dx = x(j)- x(i);

dy = y(j)- y(i);

dz = z(j)- z(i);

dr = sqrt(dx^2+dy^2+dz^2);

for k = 1:n_bond_types

if (dr> 0.9999*dr_Bond(k) && dr <1.0000001*dr_Bond(k))

disp([nb, k, i, j]);

nb = nb+1;

end

end

end

end

Nbonds = nb - 1;

disp(['Number of bonds= ', num2str(Nbonds)]);