There's a whole new implementation of the Image Based Lighting system in Turtle 4, so let's check it out and see how it works. You've probably already been using final gathering with a texture mapped sky light for high quality renders. IBL is very similar, but there are some differences between the two that are important to know about when you're choosing the weapon for your next project.

When using final gathering, the sky light is sampled by brute-force, and you often have to blur the environment texture to avoid noise in the final image. Image Based Lighting instead analyzes the image instead, and stratifies it in a smart way so that bright areas get sampled more by Turtle. IBL by itself generates higher quality shadows than an equivalent final gathering set-up.

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