How to do a 3D circle in matlab

조회 수: 86 (최근 30일)
john pag
john pag 2013년 6월 17일
댓글: Rudranarayan Kandi 2018년 9월 12일
Hello,
I need a code for a 3D circle. I have the code but i can not to do 3D.
Thank you
  댓글 수: 1
Kye Taylor
Kye Taylor 2013년 6월 17일
Do you know the parametric equation for the circle in 3D?

댓글을 달려면 로그인하십시오.

채택된 답변

Sean de Wolski
Sean de Wolski 2013년 6월 17일

추가 답변 (1개)

Kye Taylor
Kye Taylor 2013년 6월 17일
편집: Kye Taylor 2013년 6월 17일
I assume you do not have a parametric form for the circle in 3D, but you do have the equation for the plane where the circle lives in 3D. In that case, i would solve this problem by creating the data in the xy-plane
% Original points, original plane
t = linspace(0,2*pi);
x = cos(t);
y = sin(t);
z = 0*t;
pnts = [x;y;z];
% unit normal for original plane
n0 = [0;0;1];
n0 = n0/norm(n0);
Then, I would rotate the circle data into a new plane
% unit normal for plane to rotate into
% plane is orthogonal to n1... given by equation
% n1(1)*x + n1(2)*y + n1(3)*z = 0
n1 = [1;1;1];
n1 = n1/norm(n1);
% theta is the angle between normals
c = dot(n0,n1) / ( norm(n0)*norm(n1) ); % cos(theta)
s = sqrt(1-c*c); % sin(theta)
u = cross(n0,n1) / ( norm(n0)*norm(n1) ); % rotation axis...
u = u/norm(u); % ... as unit vector
C = 1-c;
% the rotation matrix
R = [u(1)^2*C+c, u(1)*u(2)*C-u(3)*s, u(1)*u(3)*C+u(2)*s
u(2)*u(1)*C+u(3)*s, u(2)^2*C+c, u(2)*u(3)*C-u(1)*s
u(3)*u(1)*C-u(2)*s, u(3)*u(2)*C+u(1)*s, u(3)^2*C+c];
% Rotated points
newPnts = R*pnts;
Visualize:
plot3(newPnts(1,:),newPnts(2,:),newPnts(3,:),'ko')
  댓글 수: 3
Vince
Vince 2018년 1월 13일
Fantastic answer for creating a circle located in arbitrary 3D space!
Rudranarayan Kandi
Rudranarayan Kandi 2018년 9월 12일
very nice approach for plotting in a different plane with normal specified.!!!! Cheers!!!

댓글을 달려면 로그인하십시오.

카테고리

Help CenterFile Exchange에서 2-D and 3-D Plots에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by