Breast physics

File:Street Fighter V breast physics.gif (seen on Chun-Li on the right), which were later changed in a patch]]

In video games, breast physics or jiggle physics are a feature that makes a female character's breasts bounce when she moves, sometimes in an exaggerated or unnatural manner.

History

File:MAI KOFXIII stance.gif is a popular fighting game character who is a notable early demonstration of breast physics technology. An example of Mai's famous breast-bounce effect as seen in 2010's The King of Fighters XIII, in which her design and stance are based on her first appearance in the Fatal Fury series.{{cite web | url=http://game.snkplaymore.co.jp/official/kof-xiii/blog/archives/2010/06/post_16.html| script-title=ja:チーム紹介女性格闘家チーム|publisher=SNK Playmore| date=June 18, 2011|access-date=August 10, 2011| language=ja}}]]

The first video game in which breast physics were a notable feature was the fighting game Fatal Fury 2 (1992), which featured the fighter Mai Shiranui, who had noticeably jiggly breasts.{{cite news|last1=Hernandez |first1=Patricia |title=How Video Game Breasts Are Made (And Why They Can Go Wrong) |url=http://kotaku.com/how-video-game-breasts-are-made-and-why-they-can-go-so-1687753475 |accessdate=12 February 2017 |work=Kotaku |date=24 February 2015 |url-status=live |archiveurl=https://web.archive.org/web/20170204024702/http://kotaku.com/how-video-game-breasts-are-made-and-why-they-can-go-so-1687753475 |archivedate=4 February 2017 }} Pronounced breast physics have since remained a staple feature of many fighting games, perhaps in part because these games contain fewer character models than other games and can therefore afford to animate their characters in more detail. The Dead or Alive series (1996–), in particular, has become identified with the "outlandish" physics of both its fighting moves and its female characters' breasts; its developer Team Ninja created the term "breast physics".{{Cite web |url=https://hothardware.com/news/dead-or-alive-extreme-3s-gratuitous-ta-deemed-too-sexist-for-american-european-audiences |title=Dead or Alive Extreme 3's Gratuitous T&A Deemed Too Sexist For American, European Audiences |last=Williams |first=Rob |date=2015-11-26 |website=HotHardware |language=en-us |access-date=2020-01-23}}

On occasion, this aspect of fighting games has caused particular attention, such as when the 2016 game Street Fighter V had the fighter Chun-Li's breasts move like large water balloons when she was chosen as the second player's character in the selection screen. Although this behavior was noticed by media even before the game's release, it remained present in the released version of the game.{{cite news|last1=Hernandez |first1=Patricia |title=Street Fighter V's Ridiculous Breast Physics Are Still In The Game |url=http://kotaku.com/street-fighter-vs-ridiculous-breast-physics-are-still-i-1759446755 |accessdate=12 February 2017 |work=Kotaku |date=16 February 2016 |url-status=live |archiveurl=https://web.archive.org/web/20170213163628/http://kotaku.com/street-fighter-vs-ridiculous-breast-physics-are-still-i-1759446755 |archivedate=13 February 2017 }} The game's publisher Capcom attributed it to a bug and later removed it by a patch.{{cite news|last1=Yin-Poole |first1=Wesley |title=Capcom patches out Chun-Li's ridiculous boob physics |url=http://www.eurogamer.net/articles/2016-03-29-capcom-patches-out-chun-lis-ridiculous-boob-physics |accessdate=12 February 2017 |work=Eurogamer |date=29 March 2016 |language=en-UK |url-status=live |archiveurl=https://web.archive.org/web/20170213001625/http://www.eurogamer.net/articles/2016-03-29-capcom-patches-out-chun-lis-ridiculous-boob-physics |archivedate=13 February 2017 }}

In reaction to the prevalence of big, bouncy breasts in video games, games writer Jenn Frank initiated a "boob jam" in 2013.{{cite web|title=The Boob Jam|url=http://theboobjam.com/|website=theboobjam.com|accessdate=27 July 2017|language=en}} The purpose of the initiative was to create games that deal "with an aspect of female breasts other than the fact that they're sexy and fun to look at".{{cite news|title='Boob Jam' explores unsexy side of breasts|url=https://www.foxnews.com/tech/boob-jam-explores-unsexy-side-of-breasts/|access-date=27 July 2017|work=Fox News|date=9 August 2013}}

Technology

Breast physics is an application of soft-body dynamics, the field of computer graphics that focuses on physical simulations of the motion and properties of deformable objects. In a game with 3D graphics, character models are composed of a skeleton of "bones" connected with joints and covered by a "skin" of textured polygons. These virtual bones do not necessarily correspond to the bones in real humans, but are required to make anything move. To make breasts or other body parts move, video game animators make the bones' joints move according to the physical rules of the game's engine.

To effect breast movement in most 3D games, the breast's bones are equipped with "springs" that make the breasts bounce when the rest of the skeleton moves. The setup and strength of these springs determines the strength of the breast bounce. Alternatively, the motion of the breasts may be governed by custom-written software, but this is more time-consuming and therefore rarer than using springs, which are a built-in feature in many game engines.

Unnatural breast physics

Some video games feature breast movements that appear unnatural or exaggerated. This may result from limitations of the "springs" system, which is better suited to animating rigid bodies rather than soft objects like breasts. In some games, however, exaggerated breast physics are intentional. This may be caused by increasing the bounce effect in order to make it noticeable even when a character is standing still and talking, which may result in wildly exaggerated bounces when she actually moves.

Ultimately, however, according to game developer Tim Dawson, if a video game features unnatural breast movements, "it's because somebody wanted them to look that way".

Breast physics in individual games

=Games noted for exaggerated breast physics=

Games noted by video game publications for their exaggerated breast physics include the following:

Fatal Fury 2, fighting game (1992){{cite news|last1=Knight |first1=Rich |title=The 10 Most Ridiculous Uses of Jiggle Physics in Games |url=http://www.complex.com/pop-culture/2012/02/the-10-most-ridiculous-uses-of-jiggle-physics-in-games/ |accessdate=12 February 2017 |work=Complex |date=6 February 2012 |language=en |url-status=live |archiveurl=https://web.archive.org/web/20160916032831/http://www.complex.com/pop-culture/2012/02/the-10-most-ridiculous-uses-of-jiggle-physics-in-games/ |archivedate=16 September 2016 }}
Mortal Kombat, fighting game series (1992–)
The King of Fighters, fighting game series (1994–)
Soulcalibur, fighting game series (1995–)
Dead or Alive, fighting game series (1996–). The bouncing was reduced in Dead or Alive 6, which uses a "natural" body physics engine.{{cite news |last1=Yin-Poole |first1=Wesley |title=Dead or Alive 6 tones down female character sexualisation |url=https://www.eurogamer.net/articles/2018-06-18-dead-or-alive-6-tones-down-female-character-sexualisation |accessdate=28 September 2018 |work=Eurogamer.net |date=18 June 2018 |language=en}}
Ready 2 Rumble Boxing, sports game (1999)
Conker's Bad Fur Day, platformer (2001), in which breasts are used as springboards
Lula 3D, adult adventure game (2005), which used motion capture and advertised "Bouncin' Boobs Technology" on its boxart.{{cite web|title=Why the Adults Only rating may be pointless and harmful to games as an art form|url=http://www.polygon.com/2014/2/10/5362502/adults-only-rating-pointless-and-harmful-games-as-art-form|url-status=live|archive-url=https://web.archive.org/web/20140403164014/http://www.polygon.com/2014/2/10/5362502/adults-only-rating-pointless-and-harmful-games-as-art-form|archive-date=April 3, 2014|access-date=March 22, 2014|work=Polygon|date=10 February 2014 |publisher=Vox Media|df=mdy-all}}{{cite web|title=A history of (muted) violence|url=http://www.polygon.com/features/2013/8/8/4595050/adults-only-ao-games|url-status=live|archive-url=https://web.archive.org/web/20140322224633/http://www.polygon.com/features/2013/8/8/4595050/adults-only-ao-games|archive-date=March 22, 2014|access-date=March 22, 2014|work=Polygon|date=8 August 2013 |publisher=Vox Media|df=mdy-all}}{{cite web|last=Gibson|first=Ellie|date=January 20, 2006|title=Lula 3D|url=http://www.eurogamer.net/articles/r_lula3d_pc|website=Eurogamer|publisher=Gamer Network|accessdate=February 12, 2011}}{{cite web|last=Sluganski|first=Randy|date=November 28, 2006|title=Lula 3D|url=http://www.justadventure.com/reviews/Lula3D/Lula3D.shtm|url-status=dead|website=Just Adventure|archiveurl=https://web.archive.org/web/20071002040832/http://www.justadventure.com/reviews/Lula3D/Lula3D.shtm|archivedate=October 2, 2007|accessdate=March 3, 2018}}
Resident Evil, action game (2002/2015){{cite news|last1=Gray|first1=Kate|title=Let me get something off my chest about boob physics in video games|url=https://www.theguardian.com/technology/2015/jan/21/boobs-breasts-physics-video-game|accessdate=29 July 2017|work=The Guardian|date=21 January 2015}}
Ninja Gaiden Sigma 2, action game (2009), where the breasts' wobble can be separately controlled by the player
Skullgirls, fighting game (2012)
Lightning Returns: Final Fantasy XIII, role-playing game (2013){{cite magazine|last1=Kohler|first1=Chris|title=With Final Fantasy XIII's breast jiggle physics, Square Enix has lost the plot|url=https://www.wired.co.uk/article/final-fantasy-is-dead|accessdate=27 July 2017|magazine=WIRED UK|date=31 July 2013}}
Metal Gear Solid V: The Phantom Pain, action game (2015){{cite news|last1=Hansen |first1=Steven |title=Metal Gear Solid V infinity boobs: More proof women are hard to animate |url=https://www.destructoid.com/metal-gear-solid-v-infinity-boobs-more-proof-women-are-hard-to-animate-315691.phtml |accessdate=12 February 2017 |work=Destructoid |date=15 October 2015 |language=en |url-status=live |archiveurl=https://web.archive.org/web/20170213090354/https://www.destructoid.com/metal-gear-solid-v-infinity-boobs-more-proof-women-are-hard-to-animate-315691.phtml |archivedate=13 February 2017 }}
Marvel Rivals, hero shooter game (2024), particularly for Emma Frost.{{Cite web |last=Valens |first=Ana |date=2025-04-04 |title=‘Marvel Rivals’ Breastily Convinced Me to Jiggle My Way Back |url=https://www.vice.com/en/article/marvel-rivals-breastily-convinced-me-to-jiggle-my-way-back/ |access-date=2025-04-05 |website=VICE |language=en-US}} Various unofficial mods have been released that add exaggerated breast physics to other characters, like Black Widow, Psylocke, Dagger, Luna Snow, Magik, Storm, and Squirrel Girl.

=Games otherwise noted for their breast physics=

Policenauts (PlayStation version in 1996): Hideo Kojima "will never forget arguing over the 'breast jiggle issue' with Shuhei Yoshida".{{Cite web|url=https://kotaku.com/hideo-kojimas-memoirs-of-the-playstation-1669705939|title=Hideo Kojima's Memories of the PlayStation|last=Nakamura|first=Toshi|date=December 11, 2014|website=Kotaku|language=en-US|archive-url=https://web.archive.org/web/20160824131050/http://kotaku.com/hideo-kojimas-memoirs-of-the-playstation-1669705939|archive-date=August 24, 2016|url-status=live|access-date=February 5, 2019|df=mdy-all}}
Fortnite Battle Royale (2017) used breast physics in a character model (Calamity) released in September 2018, which attracted controversy. The developer Epic Games later removed it as an "embarrassing and unintended" mistake.{{cite web|url=https://www.pcgamer.com/fortnites-boob-physics-are-an-embarrassing-and-unintended-mistake-will-be-fixed/|title=Fortnite's boob physics are an 'embarrassing and unintended' mistake, will be fixed|last=Chalk|first=Andy|date=September 27, 2018|work=PC Gamer|accessdate=September 27, 2018}}
Conan Exiles (2017) allows players to customize a female character's breast size or a male character's penis size. The size affects how much either piece of anatomy jiggles.{{cite web | url = https://www.pcgamer.com/conan-exiles-dick-slider/ | title = Conan Exiles has an 'endowment' slider and genital physics | first = Christopher | last = Livingstone | date = January 31, 2017 | accessdate = September 27, 2018 | work = PC Gamer }}{{cite web | url = https://www.pcgamer.com/conan-exiles-artist-had-reference-dicks-on-her-screen-for-a-week-while-designing-dong-slider/ | title = Conan Exiles director explains dong slider implementation | first= Joe | last = Donnelly | date = January 25, 2018 | accessdate = September 27, 2018 | work = PC Gamer }}