A virtual set or virtual background for green screen is basically any digital background, 3D environment, film set or television studio backdrop that is replaced for a solid background color (in most cases green).

To use virtual sets inside of OBS you need to create a scene with a background and foreground. Using your camera with a green screen background, you can apply the chroma-key filter to remove the background. Using the OBS layering system, you can put your video in-between the background and foreground.