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Originally posted by xiegangmai at 2011-04-11 07:36:08:
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Originally posted by adder8810 at 2011-04-11 01:04:46:
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Originally posted by adder8810 at 2011-04-11 10:18:50:
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clear
x = 0 : pi / 10 : 2 * pi;   % x·¶Î§
y = 2 + cos( x );   % y = f( x );

[ X, Y, Z ] = cylinder( y, 20 );    % »ØתÖÐÐÄÊÇzÖá

subplot( 1, 3, 1 )  % ÈÆzÖáÐýת
surf( X, Y, Z )
xlabel( 'x' )
ylabel( 'y' )
zlabel( 'z' )
axis square

Sx = reshape( X, size( X, 1 ) * size( X, 2 ), 1 );
Sy = reshape( Y, size( Y, 1 ) * size( Y, 2 ), 1 );
Sz = reshape( Z, size( Z, 1 ) * size( Z, 2 ), 1 );

subplot( 1, 3, 2 ) % ½«»ØתÖÐÐÄÓÉzÖáתµ½xÖᣬÐèÈÆyÖáÐýת90¶È
theta = pi / 2;
% ͼÐα任¾ØÕó
M = [ cos( theta ), 0, -sin( theta );
    0, 1, 0;
    sin( theta ), 0, cos( theta ) ];

S1 = [ Sx, Sy, Sz ] * M;
X1 = reshape( S1( :, 1 ), size( X, 1 ), size( X, 2 ) );
Y1 = reshape( S1( :, 2 ), size( X, 1 ), size( X, 2 ) );
Z1 = reshape( S1( :, 3 ), size( X, 1 ), size( X, 2 ) );

surf( X1, Y1, Z1 )
xlabel( 'x' )
ylabel( 'y' )
zlabel( 'z' )
axis square



subplot( 1, 3, 3 )  % ½«»ØתÖÐÐÄÓÉzÖáתµ½yÖᣬÐèÈÆxÖáÐýת-90¶È
theta = -pi / 2;
% ͼÐα任¾ØÕó
M = [ 1, 0, 0;
    0, cos( theta ), sin( theta );
    0, -sin( theta ), cos( theta ) ];

S2 = [ Sx, Sy, Sz ] * M;
X2 = reshape( S2( :, 1 ), size( X, 1 ), size( X, 2 ) );
Y2 = reshape( S2( :, 2 ), size( X, 1 ), size( X, 2 ) );
Z2 = reshape( S2( :, 3 ), size( X, 1 ), size( X, 2 ) );
surf( X2, Y2, Z2 )
xlabel( 'x' )
ylabel( 'y' )
zlabel( 'z' )
axis square