The idea behind chroma keying is to create a color comparison mask from which to generate an alpha mask. But still, the value of being able to previs and test our chroma key right away in the editor can be very useful. That means we need to assume that our real-time version will be fairly basic in comparison, and will probably require lots of content-dependent tweaks to look acceptable. Certain projects, such as live broadcasts, will tend to use expensive dedicated hardware solutions. Many of the things Nuke will do to get a very high-quality chroma key alpha can be computationally intensive. Numerous software packages offer pretty advanced methods for this, such as Nuke. I will preface this by saying that getting high-quality chroma keying results is difficult and often requires different techniques to be mixed.
We recently added a UE4 plugin called Composure which makes it easier to mix and match post-processing and rendering elements, and that could be a great place to try out using a live chroma key material. The process of extracting an alpha from a green screen is referred to as chroma keying. This usually involves a green screen setup of some kind which can be a bit more challenging since you won't have a built-in alpha. While most AR demos are about compositing digital objects onto live video, some projects require mixed reality, involving projecting live subjects into digital scenes. With all this going on, it seems like a good time for some examples on how you can set up a chroma key material in UE4. You can read about that, including some amazing projects, in Tim Sweeney's post surrounding WWDC here.
While it was in the release notes, our notes can be pretty long and it is easy to forget about features that are buried deep within them, especially if you had no reason to use them at the time.ĪR is on the rise with many new tools and devices being supported all the time UE4's recent support of ARKit and ARCore are a testament to this. That post led to me mocking up a very basic chroma key function called Chroma Key Alpha that was added to UE4 a while ago. A bit over two years ago, someone on the UE4 AnswerHub asked about chroma keying (a.k.a.
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