Paper-worthy rendering in MATLAB

MATLAB is not a great tool for creating 3D renderings. However, the learning curves for most commercial rendering tools are quite steep. Other tools like Mitsuba can create beautiful pictures, but can feel quite cumbersome for rendering pure geometry rather than the physical scenes their designed for.

Over the years, I’ve developed a way of creating plots of 3D shapes in MATLAB using a few extra functions in gptoolbox. This started as a way to just make images from research prototypes more palatable, but eventually became the usual way that I render images for papers. If the code for my research is already written in MATLAB then one huge advantage is that every image in my paper can have a *.m script that deterministically generates the result and the corresponding image with user intervention. This helps with reproducibility, editing and sharing between collaborators.

Here’s a “VFX Breakdown” of rendering a 3D shape in MATLAB.

t = tsurf(F,V);
set(gcf,'COlor',0.94*[1 1 1]);
teal = [144 216 196]/255;
pink = [254 194 194]/255;
bg_color = pink;
fg_color = teal;
for pass = 1:10
  switch pass
  case 1
    % blank run
    axis([-209.4       119.38      -181.24       262.67      -247.28 247.38]);
  case 2
    axis equal;
    axis([-209.4       119.38      -181.24       262.67      -247.28 247.38]);
    axis vis3d;
  case 3
    t.EdgeColor = 'none';
  case 4
    set(t,fphong,'FaceVertexCData',repmat(fg_color,size(V,1),1));
  case 5
    set(t,fsoft);
  case 6
    l = light('Position',[0.2 -0.2 1]);
  case 7
    set(gca,'Visible','off');
  case 8
    set(gcf,'Color',bg_color);
  case 9
    s = add_shadow(t,l,'Color',bg_color*0.8,'BackgroundColor',bg_color,'Fade','infinite');
  case 10
    apply_ambient_occlusion(t,'AddLights',false,'SoftLighting',false);
  end

  vidObj = VideoWriter(sprintf('nefertiti-%02d.mp4',pass),'MPEG-4');
  vidObj.Quality = 100;
  vidObj.open;
  thetas = linspace(30,-30,450);
  for theta = thetas(1:end-1)
    view(theta,30);
    drawnow;
    vidObj.writeVideo(getframe(gcf));
  end
  vidObj.close;

end

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