This weekend, I was discussing the blog post about “Computational Fluid Dynamics and Video Games” with a friend. After the initial surprise of learning that my friend was reading my blog, the conversation turned to special effects in games and movies. He was wondering why sometimes it is obvious that a scene with fire or water special effects look fake.
The answer is actually simple: scale effects. When the special effects crew sinks a ship or designs a ball of fire, they often film a scaled-down model. The problem with this technique is that the actual physics of the fire or water will also scale down! As a consequence, a huge ball of fire over a city may remind you of the dead leaves fire you had last fall in your garden. Or a water rushing over a sinking boat may remind you of what you saw when you were sinking toy boats in the bathtub when you were a kid. Continue reading