I remember the first time I started looking into shadows. It was back when I first started working with 3D graphics and I had this naive idea that 3D graphics were so awesome because they were simulating nature. Learning about real time shadow rendering techniques quickly killed that idea. Learning about other aspects of real time 3D rendering like geometry and lighting I suspended the realization that it is all just smoke and mirrors, by imagining that if my computer were just faster, I might be able to take into account enough detail to actually be simulating how light works, rather than just making a nice picture with a pseudo-approximation of how light works. But when it comes to shadows, that rationalisation rolls over and dies. The methods used to create the appearance of shadows in real time rendering (and as far as I’ve researched, in offline rendering as well) are far removed from the real world physics that create shadows.

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