Cel based animation is considered the most traditional form of animation; the technique of cel based animation is to draw each individual frame and piece them together to seem like fluent motion. Cel based animation is typically 2D based however, many people draw with 3D perspective during cel based. Cel based technique was popular in the early days of animations with Disney and Hanna Barbera using it commonly; This technique of animation was used in "Snow White And The Seven Dwarfs", "Sleeping Beauty" as well as "The Flintstones", "Tom and Jerry" and "Scooby-Doo!". An advantage of cel based animation is that it gives a classic look popular among the Disney movies, also at the time cel based animation was an opportunity to add early CGI to movies such as Mary Poppins, Bedknobs and Broomsticks etc. Cel based animation also brought technicolor to a mainly black and white dominant era, Another advantage is that this technique can be drawn freehand however this adds on to the disadvantage, as creating a freehand full length film would take a massive amount of team with multiple artists. Multiple artists means lots of money spent on hiring them, especially if you're wanting it done within a specific time period.
If the animation needs voices to add to the narrative, it is common that the voice tracks will be recorded prior to the actual animation; this is so the animation can sync up better to the voice. However, in Japanese Anime, it is more common that they would record and sync up the audio in post to the animation.
