An illusion is a distortion of the senses, which can reveal how the human brain normally organizes and interprets sensory stimulation. Though illusions distort our perception of reality, they are generally shared by most people.
An optical illusion is characterized by visually perceived images that are deceptive or misleading. Therefore, the information gathered by the eye is processed by the brain to give, on the face of it, a percept that does not tally with a physical measurement of the stimulus source. A conventional assumption is that there are physiological illusions that occur naturally and cognitive illusions that can be demonstrated by specific visual tricks that say something more basic about how human perceptual systems work. The human brain constructs a world inside our head based on what it samples from the surrounding environment. However, sometimes it tries to organize this information it thinks best while other times it fills in the gaps.This way in which our brain works is the basis of an illusion.
Visual transitions are animations that introduce a new visual component to the scene, usually by replacing a component already in the scene. A good example of a visual transition is a fade-out on TV—it is a visual effect that informs the viewer that something is ending and something new has started.
A film transition is a technique used in the post-production process of film editing and video editing by which scenes or shots are combined. Most commonly this is through a normal cut to the next shot. Most films will also include selective use of other transitions, usually to convey a tone or mood, suggest the passage of time, or separate parts of the story. These other transitions may include dissolves, L cuts, fades (usually to black), match cuts, and wipes.
Every film today, whether it be live-action, computer generated, or traditional hand-drawn animation is made up of hundreds of individual shots that are all placed together during editing to form the single film that is viewed by the audience. The shot transition is the way in which two of these individual shots are joined together.