PHYS123 Course Blog: September 2014

"The Laws Of Physics In An Animated Universe - Ultra Street Fighter IV"

In the world of video games, true to life physics are almost always never fully realized. Similar to animated shows or movies, physics in video games are very often not only to emphasize character or creature movements but also to cater into its "fun factor". In the game Ultra Street Fighter IV produced by Capcom, the overall style of the game is geared toward cartoon visuals more so than to achieve a hyper-realism look. This naturally in turn allowed its developers to break free of the boundaries of real life physics and utilize creativity to create very unique characters with over-the-top move sets.

One of the first things one may notice upon first glance of the game is that the characters have very exaggerated and highly stylized human body proportions. While this alone does not particularly pose as an obvious example of the game world's physics, it does propose as a sort of foreshadowing of the games backdrop and concept. This visual style of the game lends itself well to the core concept of squash and stretch in traditional animation. First off, as a fighting game there are more than a few moments of punches and kicks making impact on each respective character in the match. As characters perform what are called "Ultra moves" or "Super moves", these attacks trigger pre-rendered animated cut scenes. In these moves, the viewers camera is often closely cropped during each of the performing characters attacks. If one were to pull a freeze frame from one of these animations, it would reveal that the character receiving a blow would have his or her body extremely contort in reaction to a punch or kick being received. In contrast, if someone were to receive a blow to the face in real life, while a face may contort to a certain degree it would be barely noticeable to the naked eye. An in-depth close up study of the animations in Street Fighter however would reveal that the body contorts past its limits going as far as stretching the underlying skeletons of the characters. A great example that would be easy to point out is Dhalsim as all of his normal attacks include him stretching his limbs across nearly the entire screen to hit the opposing character from far away.

In the same vein as this squash and stretch aspect of the game, similar real-life inconsistencies come across in the traditional animation rule of action and reaction. To put simply, every character in the game has access to six different buttons: a light punch and kick, a medium punch and kick, and a heavy punch and kick. While each attack will do varying degrees of damage accordingly (a light punch will do far less damage than a heavy punch, for example), this is not reflected in the actual reactions of the character being hit. In real world physics, the rule states "every action has an equal and opposite reaction." With this rule in mind, in theory a characters reaction to a light attack would yield mild results while a reaction to a heavy attack would yield a much more violent reaction. While this would hold true in a true to life example, the game does not follow suit. Due possibly to the constraints of video game production, every time a character is hit, he or she reacts with a preset "hit" animation, meaning every time a character is hit with either a light attack or heavy attack, they react accordingly to the same degree of reaction every time. However, this does work to the game's credit in that as a character is attacked, the resulting blow helps sell the "impact" of these super-powered characters and really make the user feel in control of what could be considered a super human. Another aspect where the action and reaction rule is broken is in some rare cases where a character may jump over the opposing character and attack them from the other side. Due to certain rules in the game, this would still result in a hit, but in this instance the attacked characters reaction would result in him or her "falling back" not in the opposite direction but rather in the same direction. While this allows a user to control their attacks and surprise their enemy by hitting them from the other side, the reaction from the attacked character does not follow the real world rule that their reaction should be opposite of the opposing action.

One of the biggest factors in real world physics is the force of gravity, and while this force factors into many formulas here on earth, the same physics do not apply in the same way in the Street Fighter Universe. In the traditional animation space, "heavy" character animations are often tweaked in such a manner that they really "feel" heavy. This may include hunkering slow movements or falls that really shake the ground. This same rule applies to the game as well, as smaller sized fighters move quickly from left to right of screen and have longer air times while heavy characters may not jump very high at all. While these tricks do their job of selling the weight of the characters and while some of these aspects may be true to an extent in real life, they do not necessarily follow the real world rules of the force of gravity. Here on earth, with disregard to external forces of friction such as air resistance, an object with a heavy mass in theory would fall at the same exact rate as an object with a far lighter mass. Other obvious examples of Street Fighter breaking gravity rules are characters doing airborne attacks that result in them either flying in nearly straight lines across the screen or even hovering in mid air for a given amount of time. In real world examples, these characters would have similar constant and fairly spaced parabolas if one of them were to jump across the screen. This does not hold true as each characters jump animation is significantly different in their angles of rise and fall and in varying heights.

The laws of physics are believable to certain extent in the Street Fighter universe but when compared to the real world these do not follow very closely at all. In fact, most any video game that is made will probably never have a physics based system that is one hundred percent accurate to the real world. This is due most of the time to hardware limitations, but in most cases limiting physics can be a large detriment to the outlook and original concept of a video game. While the physics in Ultra Street Fighter IV are far from possible in real life settings, it allows for a video game that is both visually pleasing and highly entertaining to play and watch in motion.

I. Introduction

A. Ultra Street Fighter IV (Video Game, 2014)

B. Thesis - The game Ultra Street Fighter IV uses a variety of over the top special effects and exaggerrated physics to present an entertaining fighting game for its audiences.

II. Body

A. Squash and Stretch

1. Characters have very exaggerated proportions in comparison to real-life humans.

2. When performing attacks and other actions, slowing down frames can reveal that limbs may stretch.

3. Especially apparent in the character Dhalsim.

4. In specific hit animations, characters can be seen being squashed or stretched in reaction to enemy character attacks.

5. While these sell the actions visually, squash and stretch does not always happen in real life situations.

B. Action and Reaction

1. Characters have a set reachtion to attacks, regardless of how strong/weak they are hit.

2. Some attacks cause character to be knocked off of their feet.

3. Occasionally characters will react to a hit in the same direction as the attack, rather than moving opposite of the force of the attack.

C. Gravity

1. While characters are varied to feel "heavy" or "light", all characters defy the physical laws of gravity in some way, shape or form.

2. Characters jump at heights much more than humanly possible.

3. Some characters may jump and hover, float, or even change directions in mid air.

4. When falling from air attacks, characters often do not follow logical parabolic arcs.

III. Conclusion

A. Laws of physics are almost always broken in not just Ultra Street Fighter IV, but in nearly all video games.

B. While developers may choose to follow the true laws of physics, almost all the time they are broken in order to deliver a fun game that is entertaining enough to bring you into its world and make you "believe" in it.