In Unity's Post Processing stack, what is the difference between a global volume and a local volume?

• A. A global volume affects only objects within a defined region; a local volume affects the entire scene.
• B. A global volume applies post-processing to the UI only; a local volume applies to 3D content.
• C. A global volume affects the entire scene; a local volume affects only within its defined boundary.
• D. A global volume requires a separate camera; a local volume uses the main camera.

Answer: (C)

Volumes in Unity's Post Processing define where effects are applied on the final image. A global volume has effectively infinite bounds, so its post-processing settings influence every pixel rendered by the camera. A local volume has a finite boundary, usually a box, and only pixels inside that box are affected by its effects. When volumes overlap, Unity blends their influences based on weighted factors such as priority, weight, and how close the camera is to a volume’s boundary, allowing smooth transitions between different looks. This makes it easy to give an interior space or a particular area its own color grading, bloom, or other effects while the rest of the scene uses the global look. The other options aren’t accurate because post-processing isn’t confined to a region by default, and you don’t need a separate camera to differentiate global versus local volumes.