Problem with the rotated object shape

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Radhika Bhagwat 2016-8-17

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编辑： William Chamberlain 2018-10-3

I have written a code for generating egg shape from ellipse using the model explained in the link below optimal shape of avian egg.The ellipse that i have generated is using normal parametric equations. x = a*cos(theta) y = b* sin(theta) Below is the figure of ellipse along with the egg shape generated by the model explained in the link above.

</matlabcentral/answers/uploaded_files/57944/ellipse%20and%20egg%20shape.jpg> next I tried to rotate the egg shape by angle pi/2 using transformation matrix; but this is what i get.

</matlabcentral/answers/uploaded_files/57945/rotated%20egg%20shape.jpg> My question is why am I not getting a proper egg shape in the rotated version?I get proper figure for an angle of pi.but not for any other angles .... pi/6,pi/3 etc....

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KSSV 2016-8-17

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I don't know how you have rotated the object/ geometry; I cannot even open the links you have given. You may consider the below code, which may help you.

clc; clear all ;
 s = [-1 -1 ; -1 1 ; 1 1 ; 1 -1 ; -1 -1]' ;  % draw square
 plot(s(1,:),s(2,:),'r') ;
 %%rotate the object 
 th = pi/4 ;   % rotate by 45 degrees
 R = [cos(th) -sin(th) ; sin(th) cos(th)] ;  % rotation matrix 
 S = zeros(size(s)) ;   % initialize rotated coordinates 
 for i = 1:size(s,2)
     S(:,i) = R*s(:,i) ;
 end
 hold on
 plot(S(1,:),S(2,:),'b') ;

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Radhika Bhagwat 2016-8-17

so then why is it looking compressed? do i need to adjust the figure window size? cause doing that gives a proper view. but then do i have to keep adjusting the window size for every angle ?Below is the adjusted figure window displaying egg shape for pi/2;