POV-Ray animation

This post continues my introduction to generating images and movies using POV-Ray.

In the last post, I showed how to render a simple scene. Now I am going to show how to animate it.

POV-Ray includes a lot of options for animation and this page provides some great tutorials and examples. However, I have always found it easier to generate animations by automatically generating different *.pov files and then rendering them as part of my workflow.

The last part is easy because you can call POV-Ray directly from the command line. (See here for many options.)

For example, once you are in the directory that contains the main POV-Ray executable, you can produce a PNG file that is 340 by 280 pixels from the scene described in c:\temp\out.pov using this command.

pvengine +W340 +H280 c:\temp\out.pov /exit

Here's some MATLAB code that will spin the camera around the previous image.

function povray_animation

r = -25;

no_of_points = 50;

x = r*cosd(linspace(0,360,no_of_points))

for i=1:no_of_points

    

    pov_file = fopen(fullfile(cd,sprintf('out%.0f.pov',i)),'w');

    fprintf(pov_file,'#include "colors.inc"\n');

    fprintf(pov_file,'background {color White}\n');

    fprintf(pov_file,'camera {location <%f,25,25>\n',x(i));

    fprintf(pov_file,'\tsky <0,0,1>\n');

    fprintf(pov_file,'\tlook_at <10,0,0>}\n');

    fprintf(pov_file,'light_source {<%f,25,25> color White}\n',x(i));

    fprintf(pov_file, ...

        'cylinder {<0,0,0>,<10,0,0>,1 texture {pigment {color Red}}}\n');

    fprintf(pov_file, ...

        'cylinder {<0,0,0>,<0,10,0>,1 texture {pigment {color Green}}}\n');

    fprintf(pov_file, ...

        'cylinder {<0,0,0>,<0,0,10>,1 texture {pigment {color Blue}}}\n');

    fprintf(pov_file, ...

        'sphere {<10,10,10>,3 texture {pigment {color OrangeRed}}}\n');

    fclose(pov_file);

    

    cd_string = 'cd c:\program files\pov-ray\v3.7\bin';

    command_string = sprintf('%s\npvengine +W340 +H280 %s +A /exit', ...

        cd_string, ...

        fullfile(cd,sprintf('out%.0f.pov',i)));

    batch_file = fopen('pov.bat','w');

    fprintf(batch_file,'%s\n',command_string);

    fclose(batch_file);

    system('pov.bat');

end

It's now easy to stitch the *.png files together to make a movie.