Making movies with subplot.

I've been trying to export an animation with subplots. So far, the code is:

syms t;
l1 = 38;
l2 = 27;
l3 = 09;
T43 = [ 1 0 0 0 ; 0 1 0 0 ; 0 0 1 l1 ; 0 0 0 1 ];
T76 = [ 1 0 0 0 ; 0 1 0 0 ; 0 0 1 l2 ; 0 0 0 1 ];
T109= [ 1 0 0 0 ; 0 1 0 0 ; 0 0 1 l3 ; 0 0 0 1 ];
video = VideoWriter('newfile.mp4','MPEG-4');
open(video);
for t = 1:1:100

      teta1 = pi+pi/4*(cos((pi/50)*t)-1); % ponto de referência  = pi (0) -- variação = ( 0 -- -180 ) 
      teta2 = (pi/2)*sin((pi/50)*t); %(7/12)*sin((pi/50)*t); % ponto de referência  = 0 (0) -- variação = (30 -- 0 -- -180 ) 
      teta3 = 0; % ponto de referência  = 0(0) -- variação =  (-90 -- 0 -- 90 )
      teta4 = pi/4*(cos((pi/50)*t)-1); % ponto de referência  = 0 (0) -- variação = (0 -- -150 )
      teta5= 0; % ponto de referência  = 0 (0) -- variação =  (-90 -- 0 -- 90 )
      teta6= 0; % ponto de referência  = 0 (0) -- variação = (-90 -- 0 -- 90 )
      teta7= 0; % ponto de referência  = 0 (0) -- variação = (-30 -- 30 )

      R10 = [ 1 0 0 0 ; 0 cos(teta1) -sin(teta1) 0 ; 0 sin(teta1) cos(teta1) 0 ; 0 0 0 1 ];
      R21 = [ cos(teta2) 0 -sin(teta2) 0 ; 0 1 0 0 ; sin(teta2) 0 cos(teta2) 0 ; 0 0 0 1];
      R32 = [ cos(teta3) sin(teta3) 0 0 ; -sin(teta3) cos(teta3) 0 0 ; 0 0 1 0 ; 0 0 0 1 ];
      R54 = [ cos(teta4) 0 -sin(teta4) 0 ; 0 1 0 0 ; sin(teta4) 0 cos(teta4) 0 ; 0 0 0 1];
      R65 = [ cos(teta5) sin(teta5) 0 0 ; -sin(teta5) cos(teta5) 0 0 ; 0 0 1 0 ; 0 0 0 1 ];
      R87 = [ 1 0 0 0 ; 0 cos(teta6) -sin(teta6) 0 ; 0 sin(teta6) cos(teta6) 0 ; 0 0 0 1 ];
      R98 = [ cos(teta7) 0 -sin(teta7) 0 ; 0 1 0 0 ; sin(teta7) 0 cos(teta7) 0 ; 0 0 0 1];
      A = [0 0 0];
      Br = R10*R21*R32*T43;
      B = [ Br(1,4) Br(2,4) Br(3,4)];
      Cr=R10*R21*R32*T43*R54*R65*T76;
      C = [ Cr(1,4) Cr(2,4) Cr(3,4)];
      Dr = R10*R21*R32*T43*R54*R65*T76*R87*R98*T109;
      D = [ Dr(1,4) Dr(2,4) Dr(3,4)];

      subplot(2,2,1)
      plot3( [A(1),B(1)] , [A(2),B(2)] , [A(3),B(3)] , 'k-o' , 'LineWidth' , 1.5 )
      hold on
      plot3( [B(1),C(1)] , [B(2),C(2)] , [B(3),C(3)] , 'b-o' , 'LineWidth' , 1.5 )
      hold on
      plot3( [C(1),D(1)] , [C(2),D(2)] , [C(3),D(3)] , 'r-o' , 'LineWidth' , 1.5 )
      xlabel('x (cm)') , ylabel('y (cm)') , zlabel('z (cm)')
      title ( 'posição de referência ')
      text(A(1),A(2),A(3),' A')
      text(B(1),B(2),B(3),' B')
      text(C(1),C(2),C(3),' C')
      text(D(1),D(2),D(3),' D')
      axis ([-100 100 -100 100 -100 100])
      grid on

      subplot(2,2,2)
      plot( [A(1),B(1)] , [A(2),B(2)] ,  'k-o' , 'LineWidth' , 1.5 )
      hold on
      plot( [B(1),C(1)] , [B(2),C(2)] ,  'b-o' , 'LineWidth' , 1.5 )
      hold on
      plot( [C(1),D(1)] , [C(2),D(2)] ,  'r-o' , 'LineWidth' , 1.5 )
      xlabel('x (cm)') , ylabel('y (cm)')
      title ( 'plano XY ')
      text(A(1),A(2),' A')
      text(B(1),B(2),' B')
      text(C(1),C(2),' C')
      text(D(1),D(2),' D')
      axis ([-100 100 -100 100 ])
      grid on

      subplot(2,2,3)
      plot( [A(1),B(1)] , [A(3),B(3)] ,  'k-o' , 'LineWidth' , 1.5 )
      hold on
      plot( [B(1),C(1)] , [B(3),C(3)] ,  'b-o' , 'LineWidth' , 1.5 )
      hold on
      plot( [C(1),D(1)] , [C(3),D(3)] ,  'r-o' , 'LineWidth' , 1.5 )
      xlabel('x (cm)') , ylabel('z (cm)')
      title ( 'plano XZ ')
      text(A(1),A(3),' A')
      text(B(1),B(3),' B')
      text(C(1),C(3),' C')
      text(D(1),D(3),' D')
      axis ([-100 100 -100 100 ])
      grid on

      subplot(2,2,4)
      plot( [-A(2),-B(2)] , [A(3),B(3)] ,  'k-o' , 'LineWidth' , 1.5 )
      hold on
      plot( [-B(2),-C(2)] , [B(3),C(3)] ,  'b-o' , 'LineWidth' , 1.5 )
      hold on
      plot( [-C(2),-D(2)] , [C(3),D(3)] ,  'r-o' , 'LineWidth' , 1.5 )
      xlabel('y (cm)') , ylabel('z (cm)')
      title ( 'plano YZ ')
      text(-A(2),A(3),' A')
      text(-B(2),B(3),' B')
      text(-C(2),C(3),' C')
      text(-D(2),D(3),' D')
      axis ([-100 100 -100 100 ])
      grid on

      M(t) = getframe();
      writeVideo(video,M);
      clf

end
close(video);

The problem is that the exported mp4 file shows only the last subplot. Any help would be greatly appreciated, thanks in advance!

Answer 1

[Image Analyst]

Apparently by default it's getting the current axes, gca. Try getting the current figure, gcf:

thisFrame = getframe(gcf);
writeVideo(video, thisFrame);

No need to save the frame. Even if you did you'd have to use a cell array, not a regular numerical array like M, so you'd have to use braces not parentheses, but like I said there's no need to do that.

Answer 2

[Guilherme Rocha]

Thank you so much. It worked perfectly.