Problem with the rotated object shape

조회 수: 1 (최근 30일)
Radhika Bhagwat
Radhika Bhagwat 2016년 8월 17일
편집: William Chamberlain 2018년 10월 3일
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....

답변 (1개)

KSSV
KSSV 2016년 8월 17일
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') ;
  댓글 수: 6
Radhika Bhagwat
Radhika Bhagwat 2016년 8월 17일
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;
William Chamberlain
William Chamberlain 2018년 10월 3일
편집: William Chamberlain 2018년 10월 3일
Add
axis equal
at the end? And use
xlim( [] ) ; ylim( [] ) ;
to control the axes extent.

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