change centre of revolution

This is the surface i got when i rotated my 2D curve about origin.

But i want to ratate it about a specific point (7.5) on x axis.

i have attached the code, please help.

u0(1,1,1) = 2256.250;

u0(2,1,1) = 2256.250;

u0(3,1,1) = 2256.250;

u0(4,1,1) = 2256.250;

u0(5,1,1) = 2256.250; %1

u0(6,1,1) = 2256.250;

u0(7,1,1) = 2256.250;

u0(8,1,1) = 2256.250;

u0(9,1,1) = 2256.250;

u0(10,1,1) = 2256.250; %2

u0(11,1,1) = 2256.250;

u0(12,1,1) = 2256.250;

u0(13,1,1) = 2256.250;

u0(14,1,1) = 2256.250;

u0(15,1,1) = 2256.250; %3

u0(16,1,1) = 2256.250;

u0(17,1,1) = 2256.250;

u0(18,1,1) = 2256.250;

u0(19,1,1) = 2256.250;

u0(20,1,1) = 2256.250; %4

u0(21,1,1) = 2256.250;

u0(22,1,1) = 2256.250;

u0(23,1,1) = 2256.250;

u0(24,1,1) = 2256.250;

u0(25,1,1) = 2256.250; %5

u0(26,1,1) = 2256.25;

u0(27,1,1) = 2256.25;

u0(28,1,1) = 2256.2502;

u0(29,1,1) = 2256.2505;

u0(30,1,1) = 2256.251; %6

u0(31,1,1) = 2256.252;

u0(32,1,1) = 2256.253;

u0(33,1,1) = 2256.2528;

u0(34,1,1) = 2256.2522;

u0(35,1,1) = 2256.2525; %7

u0(36,1,1) = 2256.2530;

u0(37,1,1) = 2256.2540;

u0(38,1,1) = 2256.2540;

u0(39,1,1) = 2256.2538;

u0(40,1,1) = 2256.2530; %8

u0(41,1,1) = 2256.2521;

u0(42,1,1) = 2256.2530;

u0(43,1,1) = 2256.2531;

u0(44,1,1) = 2256.2530;

u0(45,1,1) = 2256.2512; %9

u0(46,1,1) = 2256.2501;

u0(47,1,1) = 2256.25;

u0(48,1,1) = 2256.25;

u0(49,1,1) = 2256.25;

u0(50,1,1) = 2256.25; %10

u0(51,1,1) = 2256.25;

u0(52,1,1) = 2256.25;

u0(53,1,1) = 2256.25;

u0(54,1,1) = 2256.25;

u0(55,1,1) = 2256.25; %11

u0(56,1,1) = 2256.25;

u0(57,1,1) = 2256.25;

u0(58,1,1) = 2256.25;

u0(59,1,1) = 2256.25;

u0(60,1,1) = 2256.25; %12

u0(61,1,1) = 2256.25;

u0(62,1,1) = 2256.25;

u0(63,1,1) = 2256.25;

u0(64,1,1) = 2256.25;

u0(65,1,1) = 2256.25; %13

u0(66,1,1) = 2256.25;

u0(67,1,1) = 2256.25;

u0(68,1,1) = 2256.25;

u0(69,1,1) = 2256.25;

u0(70,1,1) = 2256.25; %14

u0(71,1,1) = 2256.25;

u0(72,1,1) = 2256.25;

u0(73,1,1) = 2256.25;

u0(74,1,1) = 2256.25;

u0(75,1,1) = 2256.25; %15

N = 75;

x = [0:0.2:14.8]';

y = [0:0.2:14.8]';

z = u0';

figure()

hold on

revolves = 100;

theta = linspace(0,2*pi,revolves);

xx = zeros(revolves,N);

yy = xx;

zz = xx;

for idx = 1:length(theta);

xrot = cos(theta(idx))*x + sin(theta(idx))*y;

yrot = -sin(theta(idx))*x + cos(theta(idx))*y;

plot3(xrot,yrot,z)

xx(idx,:)=xrot;

yy(idx,:)=yrot;

zz(idx,:)=z;

end

grid on

surf(xx,yy,zz)

[darova]

Is this correct?

Answer 1

[Payas Bahade]

Hi Ayush,

To change x-coordinate of center of revolution to 7.5, add 7.5 to the xrot equation. The new equation becomes:

xrot = 7.5+cos(theta(idx))*x + sin(theta(idx))*y;

Replace current xrot equation in for loop with above one to get required results.

Hope this helps!