Saturday, March 13, 2010

Technical Geekery: Techniques in Source Videos

In my last post I promised I would explain a little about what's so special in those videos that I linked to. Sure they're enjoyable, but what's the big deal? Well, when I first approached my adviser with this topic, I was told that some of the limitations of a game engine might hobble the project. Specifically stuff with reflections, refractions, soft shadowing, and other such things that light does in the real world.

As it turns out, that's not the case! See the images below for examples of almost all of these features that are used in the videos you just saw in my last post:

1) Reflection of the environment in his glasses. This is cheated, it's not a true reflection, but can you really tell the difference? Motion blur on any fast-moving objects is a must, and the soft shadows that you see here on his arm is visible all over the video.

2)This is a true reflection. The same effect is used for water surfaces in the engine. It's an expensive effect, but obviously not a bank breaker!

3)Light bloom and HDR. The source engine now supports a greater range of colors than the eye can see, and it varies screen exposure to mimic the human eye's attempts to compensate for lighting conditions. HDR is a topic that deserves it's own research, so let's just accept that it's part of our arsenal here and move on.

4)Dynamics and particles! Through the use of particles and sprites, the source engine contains a powerful effects system that can be used for various effects, explosions, weather, and more.

5)Depth of Field is a side-effect of our standard camera optics, and many film-makers use this to their advantage to help focus the audience's eye. In this scene, the people behind this video did exactly that, keeping the old man in focus while he examines something in the foreground.

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