In filmmaking, visual effects (abbreviated VFX) are the processes by which imagery is created or manipulated outside the context of a live action shot.
Visual effects involve the integration of live-action footage and generated imagery to create environments which look realistic, but would be dangerous, expensive, impractical, or impossible to capture on film. Visual effects using computer-generated imagery have recently become accessible to the independent filmmaker with the introduction of affordable and easy-to-use animation and compositing software.
Rotoscoping is an animation technique used by animators to trace over motion picture footage, frame by frame, when realistic action is required. Originally, photographed live-action movie images were projected onto a glass panel and re-drawn by an animator. This projection equipment is referred to as a Rotoscope. Although this device was eventually replaced by computers, the process is still referred to as Rotoscoping. In the visual effects industry, the term Rotoscoping refers to the technique of manually creating a matte for an element on a live-action plate so it may be composited over another background.