File:Illusion of Depth and Space (10 22) - 3D Anaglyph (Red and "Green") Stereoscopic Glasses - Shadowless (3386183538).jpg

Modelled using <a href="http://www.maxon.net/pages/dyn_files/dyn_htx/htx/welcome_e.html">Maxon's</a> <a href="http://www.maxon.net/pages/products/cinema4d/cinema4d_e.html">Cinema 4D</a> <a href="http://en.wikipedia.org/wiki/Computer-generated_imagery">CGI</a> package.

A pair of 3D Anaglyph (Red and "Green") Stereoscopic Glasses, with no shadow. The green filter in these type of glasses is usually cyan - a mixture of blue and green.

In this example - the fastest to render - the spotlight from the left causes shading, but casts no shadow.

Shading and shadows are an important part of creating an illusion of space. (In conventional CGI software, shading and shadows cast are two separate things.) This scene is lit from two main sources: from directly above and also by a spotlight to the left.

In the real world, light - bouncing back and forth between a white surface and the white cardboard glasses frame - "fills in" the shaded areas. This does not happen in more basic conventional cgi, because to model every part of every surface of a object as a potential light source would require monumental conventional computer processing.

Taking into account reflected illumination - which looks more realistic - is sometime called <a href="http://en.wikipedia.org/wiki/Radiosity">Radiosity</a>. One company offering real-time (to benefit gamers) radiosity lighting solutions using <a href="http://en.wikipedia.org/wiki/Wavelet">wavelet</a> techniques is <a href="http://www.geomerics.com/">Geomerics</a>.

In the shading examples shown here I "cheated" and made the cardboard material a "self illuminator" of grey light. To see an example of a similar scene without this trick, look at the stark image <a href="https://www.flickr.com/photos/dominicspics/3386380536/">here</a>.