How to make circular Ring?

i want to make a ring. I have two circles of smaller and bigger radius and I want to substract smaller circle from bigger circle to make a ring. Please help me.

I have the code attached here.

L = 40; % Length of rectangle W = 80; % Width of rectangle angle = 0:2*pi/360:2*pi; % Angle of bending C = [L/2 0]; % centre of circle Rin = 15; %radius of inner circle Rout = 1.2*Rin; % Radius of outer circle

%% - boundary of the structure --------------------------------- xv1 = [0 0 0 0 L L 0]; % co-ordinate of rectangle yv1 = [-W/2 -W/2 W/2 W/2 W/2 -W/2 -W/2]; % co-ordinate of rectangle inc = [Rin*cos(angle')+L/2 Rin*sin(angle')]; % co-ordinate of inner circle ouc = [Rout*cos(angle')+L/2 Rout*sin(angle')]; % co-ordinate of inner circle

figure(1);plot(xv1,yv1);axis equal tight;hold on; figure(1);plot(inc(:,1),inc(:,2));axis equal tight;hold on; figure(1);plot(ouc(:,1),ouc(:,2));axis equal tight;hold on

Answer 1

[Image Analyst]

Can't you just use the code in the FAQ: http://matlab.wikia.com/wiki/FAQ#How_do_I_create_a_ring.3F

Answer 2

[Jeremy Simpson]

Try this script:

clear,clc

R = 3; %outer radius
r = 2; %inner radius
steps = 100;

theta = 0:2*pi/steps:2*pi;
r_outer = ones(size(theta))*R;
r_inner = ones(size(theta))*r;
rr = [r_outer;r_inner];
theta = [theta;theta];
xx = rr.*cos(theta);
yy = rr.*sin(theta);

zz = zeros(size(xx));
surf(xx,yy,zz)

It may or may not help. I wasn't really sure what you were wanting.