Animation Changes have taken place throughout the series, beginning after the fourth season. The first four seasons were produced using a variety of programs, mostly Power Animator. Season five was delayed six months into June so the animation staff could learn Maya. As a result, the series' animation has changed greatly.
In newer episodes, many characters' designs have changed as a result.
- Randy Marsh: As of "Chickenlover" has a different hairstyle and a dumpled chin.
- Pip Pirrup: As of "Fourth Grade" has slightly updated hair, including a small fringe visible from his hat.
- Jesus Christ: As of "Super Best Friends" has a sash.
- Jimbo Kern: As of "Night of the Living Homeless", Jimbo's waist and vest have been greatly updated with a 3-D look instead of 2-D - his shirt also now has a collar.
- Mr. Mackey: As of "Major Boobage" his shirt now has a pocket and an even collar and tie. He also has a belt.
- Herbert Garrison: As of "Eek, A Penis!" after his second sex change has an even collar and a belt.
- Gerald Broflovski: As of "Major Boobage" has a different collar and a new yamulke.
- Thomas Tucker and Mrs. Tucker: As of "Pandemic" their faces have both been given a slight clean-up, including the hair.
- Stuart McCormick: As of "Pinewood Derby" has a new collar, and a cleaned up body and hat.
- Mrs. McCormick: As of "Pinewood Derby" has cleaned up hair and a new T-shirt and pants.
- Mayor McDaniels: As of "The F Word", the Mayor has a new collar and a small medal.
- Kevin McCormick: As of "Sexual Healing" has new effects on his hair.
- Mecha-Streisand: As of "200" has a completely new and fully 3-D look.
- Dr. Alphonse Mephesto: As of "201" his wrinkles are softened and his hat now has a 3-D effect to make it's bottom visible, and his collar has been modified.
- Bradley Biggle has a more "3D" hairstyle as of "Mysterion Rises".
- Karen McCormick undergoes a redesign in "The City Part of Town".
- Beginning with Season Twelve, a lot of background characters had been redesigned.