From the course: VFX Keying: Master Course

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How to create a texture key

How to create a texture key - Nuke Tutorial

From the course: VFX Keying: Master Course

How to create a texture key

- [Narrator] So far, we've been looking at rather conventional key: luma key, chroma key, color difference key, and so on. Now it's time to look at a very unconventional way to pull a key, namely, how to pull a key on bumps and textures. Here's the theory of operation. I have this live-action shot, and like any photographic image, it's going to be unevenly lit. So if we try to pull a luma key on this, this is the result. And that's because the luma key strikes a single threshold value, and everything above appears in the key and below gets dropped out. So with unevenly lit surfaces, luma keys can't help you. But with the texture key technique, we can get a key on all the bumps, even with the uneven lighting. I mean, look at that difference there. Here's how it works. I made a little graphic for you to kind of explain the theory. Here's a cross-section of our picture showing you the falloff in the lighting from left to right, plus all the bumps. What we do, is we use a blur node to…

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