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From: Kenneth H on 11 Apr 2010 14:00
Hey guys!,

I've been working with an m-file for some time now, and it contains an animation which I use to help visualize what i'm doing and it works fine. However, I now want to use the animation for a powerpoint presentation but I cant get movie2avi to create a file for me. I need to do this before I can even start to think about getting it into a presentation. Included below is most of the code so people can see the animation. I've also posted the error message.

I don't know much about .avi files or codecs so I'm not sure if it's just something my computer is missing.
Here's the code:
______________________________________________________________
clear all
% input varibales for analysis
k = 5; %number of terms in expansion
P = 100; %load (N)
beta = 0.1; % non-dimensional damping parameter
%%%%%%%%%%%%%%%%%%%%%%%%%%%
% material and geometric constants
L = 30480; %length of beam (mm)
E = 200000; %youngs modulus (MPa)
b = 2438; % width of cross section
h = 20; % height of cross section
A = b*h;% cross sectional area of beam (mm^2)
rho = 7.8E-9;% density of beam material (kg/mm^3)
I = (b*h^3)/12;% second moment of area (mm^4)
% critical speed (resonance of first mode)
cr = (pi/L)*(sqrt(E*I/rho/A));
% speed of load
c = 70;% (mm/s)
alpha = c/cr; % non-dimensional speed parameter
omega = pi*c/L;
omegaj = ([1:k]*pi/L).^2*(sqrt(E*I/rho/A));
omegab = beta*omegaj(1);
% length vector;
x1 = 0:L/100:L;
x1 = x1';
x = repmat(x1,1,length(x1));
% time vector
tt = L/c;
step = tt/(length(x1)-1);
t1 = 0:step:tt;
t = repmat(t1,length(t1),1);
% static deflection of beam at mid span
u0 = (P*L^3)/(48*E*I); % (mm)
n = round(alpha);
if beta == 0;
u2 = 0;
else
if n > 0;
if abs(n-alpha)<0.01;
u2 = (u0/2/n^4)*(exp(-omegab*t).*sin(n*omega*t)-(n^2/beta)*cos(n*omega*t).*(1-exp(-omegab*t))).*sin(n*pi*x/L);
else
u2 = 0;
end
else
u2 = 0;
end
end
u = 0;
for j = 1:k;
if abs(j-alpha)<0.01;
u1 = 0;
else
u1 = u0*(1/(j^2*(j^2-alpha^2)))*(sin(j*omega*t)-(alpha*exp(-omegab*t)/j).*sin(omegaj(j)*t)).*sin(j*pi*x/L);
end
u = u +u1;
end
u3 = u +u2;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% creation of movie
for i = 0:1:length(x1)-1;
ax1 = (0:100)*L/100;
subplot(2,1,1), plot(ax1,-u3(:,i+1)/u0,'linewidth',1.5,'color','r');
xlabel('beam length (mm)')
ylabel('deflection (u/u0)')
title('Beam deflection under load')
axis([-0.03*L 1.03*L -1.7 0.6])
line([i*L/100 i*L/100],[0-(u3(i+1,i+1)/u0) 0.5-(u3(i+1,i+1)/u0)],'Color','k','linewidth',2)
line(i*L/100,(-u3(i+1,i+1))/u0,'Color','k','marker','V','MarkerSize',3,'linewidth',3)
% location of first supports
a = [1 0];
b = [L+1 0];
% height of support
h = 0.5;
% support 1
line([a(1) a(1)+h*L*0.03],[a(2) -h+a(2)],'linewidth',1);
line([a(1)-h*L*0.03 a(1)+h*L*0.03],[-h+a(2) -h+a(2)],'linewidth',1);
line([a(1)-h*L*0.03 a(1)],[-h+a(2) a(2)],'linewidth',1);
% support 2
line([b(1) b(1)+h*L*0.03],[b(2) -h+b(2)],'linewidth',1);
line([b(1)-h*L*0.03 b(1)+h*L*0.03],[-h+b(2) -h+b(2)],'linewidth',1);
line([b(1)-h*L*0.03 b(1)],[-h+b(2) b(2)],'linewidth',1);
%
ax2 = (0:100)*tt/100;
subplot(2,1,2), plot(ax2(1:i+1),-u3(51,1:i+1)/u0,'linewidth',1.5,'color','r');
xlabel('time (s)')
ylabel('deflection (u/u0)')
title('Deflection at the centre of the beam')
axis([-tt/20 21*tt/20 -1.7 0.6])
M(i+1) = getframe(gcf);
end

movie2avi(M,'a','compression','none','quality',100) % here is my attempt at saving the %movie for future use
___________________________________________________________________
....and the error message:
??? Error using ==> avi
Failed to open file.

Error in ==> avifile.avifile at 171
aviobj.FileHandle = avi('open',filename);

Error in ==> movie2avi at 63
avimov = avifile(filename,varargin{:});

Error in ==> unsw at 126
movie2avi(M,'a','compression','none','quality',100)
_________________________________________________________________

Thanks for any help!
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