OneUI 3.1 has a bunch of new features to play with. One of the highlighted features is an AR Doodle camera mode shortcut. Previously it was only available from the AR apps section. This time it can be found right in your camera app so you can draw AR objects on the fly and capture them on videos.
This feature was revealed by Samsung on the official presentation, but it didn't get quite popular afterwards. Potentially this move will give it a push.