Continuing on from the previous tutorial were going to have a look at using the garbage matte on the Ultimatte 12 to extend your greenscreen to infante proportions.

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In this video, I dive into solving a common problem when using a green screen with the Blackmagic Ultimatte 12 and Unreal Engine: what happens when the camera pans off the green screen? To fix this, I show you how to use the Ultimatte’s garbage matte input to isolate your subject—in this case, a little giraffe prop—and replace everything outside that cutout with your virtual background, creating a cleaner composite.

I walk you through the necessary Unreal Engine project settings, enabling custom depth and alpha through the tone mapper, and then demonstrate how to set up a simple post-process material and a translucent “magic” cube. This cube is invisible but renders in the stencil buffer, allowing it to act as a garbage matte to mask out unwanted areas. Finally, I explain how to output this matte through Ultimatte and tweak its positioning for the best effect. This tutorial is especially useful if you want more control over your keying and background replacement in virtual production setups.