<P> The object must not be altered by accident, slight smudges, dirt, hair, or dust . Feature - length productions have generally switched from clay to rubber silicone and resin cast components: Will Vinton has dubbed one foam - rubber process "Foamation". Nevertheless, clay remains a viable animation material where a particular aesthetic is desired . </P> <P> Clay animation can take several forms: </P> <P> "Freeform" clay animation is an informal term referring to the process in which the shape of the clay changes radically as the animation progresses, such as in the work of Eliot Noyes, Jr. and Ivan Stang's animated films . Clay can also take the form of "character" clay animation, where the clay maintains a recognizable character throughout a shot, as in Art Clokey's and Will Vinton's films . </P> <P> One variation of clay animation is strata - cut animation, in which a long bread - like loaf of clay, internally packed tight and loaded with varying imagery, is sliced into thin sheets, with the camera taking a frame of the end of the loaf for each cut, eventually revealing the movement of the internal images within . Pioneered in both clay and blocks of wax by German animator Oskar Fischinger during the 1920s and 1930s, the technique was revived and highly refined in the mid-1990s by David Daniels, an associate of Will Vinton, in his 16 - minute short film "Buzz Box". </P>

Name two similarities between cartoon animation and stop motion animation