# Modeling physics of heaving, bouncing, jiggling, swaying video game breasts **URL:** \ **Category:** Factual Questions\ **Created:** [May 31, 2003, 9:35am UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748 "2003-05-31T09:35:42Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [May 31, 2003, 9:35am UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/1 "2003-05-31T09:35:42Z")
Per the X-Box and related games and commericals that have a “whole lot of shakin’ going on” how do they model these? Is it all left to the artist’s imagination, do they use an intern with water filled balloons trapped to this chest, real busty women, out of work strippers, girls gone wild… what? I would imagine modeling the physics of a real (natural) pair of active female breasts would be quite complex. Do physical modeling toolkits have algorithms for female breast movement? How do they do this? ---
**Author:** ![Troy\_McClure\_SF](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troy_mcclure_sf/32/4150_2.png) [@Troy\_McClure\_SF](https://boards.straightdope.com/u/Troy_McClure_SF)\ **Post date:** [May 31, 2003, 9:52am UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/2 "2003-05-31T09:52:08Z")
Best GQ ever. Carry on. ---
**Author:** ![Armilla](https://avatars.discourse-cdn.com/v4/letter/a/e19b73/32.png) [@Armilla](https://boards.straightdope.com/u/Armilla)\ **Post date:** [May 31, 2003, 10:11am UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/3 "2003-05-31T10:11:40Z")
I’d imagine it’s done in a way similar to the one 3D modeling packages use to simulate this kind of thing. It’s usually based around a finite element materials simulator. Essentially, each vertex that makes up the object in question is assigned a mass and properties that relate it to others in the mesh (elasticity of connection, viscousness etc). Motion is applied to the mesh though gravity and key anchor points then maths does the rest. I would imagine that a game would take some shortcuts in the calculations and have heavy limits set to prevent anything weird from happening (the breasts roaming independently or failing catastrophically). It’s actually been done for a long time. I can remember a Lightwave tutorial from a number of years ago that dealt, in great detail, with jiggling breasts. Let’s see…ah, here we are. Breasts: Spring: 1000, Viscosity: 5, Resistance: 4, Hold Structure: 300, Smoothing: 2. There you have it. Of course, you can adjust the parameters for a different…er…feel. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [May 31, 2003, 10:23am UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/4 "2003-05-31T10:23:04Z")
> [@](#): > > … failing catastrophically … We are experiencing _catastrophic breast failure_! Say again, we are experiencing catastrophic breast failure! The nipples have broken free from their moorings and are leaking Half-n-Half. Structural integrity is decaying rapidly. Initiating Operation Band Name! 😃 ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [May 31, 2003, 11:36am UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/5 "2003-05-31T11:36:59Z")
It’s not just game developers who have to worry about stimulating, eh …, simulating breast motion. I once had a colleague whose physicist boyfriend did his Ph.D. in _mathematically_ modelling women’s underwear, sponsered by M&S, the main retailer of such items to the Great British Female Public. Different designs of bra will interact with breasts in different ways and it was important for a manufacturer like M&S to research ways of predicting this via computer simulation. Nice work, if you can get it … On a somewhat less dignified note, my own Ph.D. supervisor’s supervisor was once persuaded, in the interests of the public understanding of physics, to appear on TV explaining simple harmonic motion. What the production company didn’t tell him was that it was for an item about breasts. Or that they were replacing the background to him as the talking head with slow motion footage of a female jogger, umm, illustrating the concept. In ample fashion. ---
**Author:** ![refusal](https://avatars.discourse-cdn.com/v4/letter/r/ac91a4/32.png) [@refusal](https://boards.straightdope.com/u/refusal)\ **Post date:** [May 31, 2003, 1:53pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/6 "2003-05-31T13:53:57Z")
Disclaimer: I have never tried to mode the physics of breasts. However, it’s possible to model the behaviour of a non-rigid solid subject to external forces by considering it as being made up of a number of points (nodes) connected by springs, forming a lattice. Each spring can be modelled using Hooke’s law (F = -kx, where F is the force, k is constant, and x the displacement from its rest position). At each tick of time you calculate the forces on each node and work out its acceleration and consequently velocity and position. With a homogenous solid like jelly, each of these springs behaves the same, making it simple to construct a model, even if it is computationally intensive. It is fairly simple to construct nice wobbly animations in 2 or 3 dimensions (which I have done a very basic version of in 2D). Modelling a breast is a little more complex, since they combine fatty matter with more rigid connective tissue and have an outer elastic skin which has a stronger pull. Nonetheless, the same principles could be applied. Such techniques can also be combined with the simulation of human muscle movement and other simulations of human physiology. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [May 31, 2003, 3:14pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/7 "2003-05-31T15:14:13Z")
> [@](#): > > I would imagine modeling the physics of a real (natural) pair of active female breasts would be quite complex. And the ironic part is that the very people who devote the most time to modeling virtual breasts have the least experience with the real thing. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [May 31, 2003, 3:29pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/8 "2003-05-31T15:29:28Z")
> [@](#): > > \*Originally posted by refusal \* > \*\*Modelling a breast is a little more complex, since they combine fatty matter with more rigid connective tissue and have an outer elastic skin which has a stronger pull. Nonetheless, the same principles could be applied. Such techniques can also be combined with the simulation of human muscle movement and other simulations of human physiology. \*\* How bad does it look if you just treat the breast as a homogenous solid? ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [May 31, 2003, 3:52pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/9 "2003-05-31T15:52:46Z")
> [@](#): > > \*Originally posted by ultrafilter \* > \*\*How bad does it look if you just treat the breast as a homogenous solid? \*\* It gives homogenized milk. ---
**Author:** ![Sock\_Munkey](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@Sock\_Munkey](https://boards.straightdope.com/u/Sock_Munkey)\ **Post date:** [May 31, 2003, 3:56pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/10 "2003-05-31T15:56:48Z")
Heck, half the breasts in hollywood ARE composed of homogenous solids… ---
**Author:** ![Alphagene](https://avatars.discourse-cdn.com/v4/letter/a/8e7dd6/32.png) [@Alphagene](https://boards.straightdope.com/u/Alphagene)\ **Post date:** [May 31, 2003, 4:11pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/11 "2003-05-31T16:11:15Z")
[Gettin’ Jiggly Wit It](http://www.wired.com/wired/archive/10.11/play.html?pg=2) ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [May 31, 2003, 4:45pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/12 "2003-05-31T16:45:24Z")
But will they come out with a video game for women where the men are naked and their scrotum and penis dangles in the breeze, as well as perk up when aroused? Probably not because the single algorithm is too simple – it’s either on or off. 😃 ---
**Author:** ![NutWrench](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nutwrench/32/20193_2.png) [@NutWrench](https://boards.straightdope.com/u/NutWrench)\ **Post date:** [May 31, 2003, 6:38pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/13 "2003-05-31T18:38:05Z")
Microsoft is working closely with hardware vendors to incorporate DirectBoobie™ into the DirectX10 release. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [July 11, 2003, 3:35pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/14 "2003-07-11T15:35:11Z")
> [@](#): > > \*Originally posted by Duckster \* > \*\*But will they come out with a video game for women where the men are naked and their scrotum and penis dangles in the breeze, as well as perk up when aroused? > > Probably not because the single algorithm is too simple – it’s either on or off. > 😃 \*\* Well, there’s always the transition period . . . I would imagine if there was a preceived demand, the game designers would come up with one. DD ---
**Author:** ![Find\_Friends](https://avatars.discourse-cdn.com/v4/letter/f/c37758/32.png) [@Find\_Friends](https://boards.straightdope.com/u/Find_Friends)\ **Post date:** [July 11, 2003, 4:59pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/15 "2003-07-11T16:59:31Z")
> [@](#): > > \*Originally posted by Little Nemo \* > \*\*And the ironic part is that the very people who devote the most time to modeling virtual breasts have the least experience with the real thing. \*\* Ironic perhaps, but not very surprising… 🆒 * * * True Blue Jack ---
**Author:** ![GargoyleWB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gargoylewb/32/199_2.png) [@GargoyleWB](https://boards.straightdope.com/u/GargoyleWB)\ **Post date:** [July 11, 2003, 6:15pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/16 "2003-07-11T18:15:12Z")
The greatest research tool on this matter was given to us by Monty Python in The Meaning of Life, with the slo-mo topless female lacrosse squad. Having endlessly scrutinized the footage over the years, frame-by-frame, reverse, stills, high-speed, IMHO the mathematics involved are just too complex for human understanding…unless it lies hidden in the harmonics…it just might…this bears further research… “This man is about to die…” ---
**Author:** ![GrizzRich](https://avatars.discourse-cdn.com/v4/letter/g/7ba0ec/32.png) [@GrizzRich](https://boards.straightdope.com/u/GrizzRich)\ **Post date:** [July 11, 2003, 6:47pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/17 "2003-07-11T18:47:15Z")
Oh my God… They’re BOOBIES few cryin’ out loud? Can’t we just appreciate them for what they are?! …mmmmm…booooo-oooobies… ---
**Author:** ![jmonster](https://avatars.discourse-cdn.com/v4/letter/j/dbc845/32.png) [@jmonster](https://boards.straightdope.com/u/jmonster)\ **Post date:** [July 11, 2003, 7:02pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/18 "2003-07-11T19:02:10Z")
After playing Bloody Roar 3 and a few other games, I’m convinced that the PlayStation2 has a special boob-jiggling chip that programmers can just hook into. And, damn, that chip does a fine job… ---
**Author:** ![Bongmaster](https://avatars.discourse-cdn.com/v4/letter/b/6a8cbe/32.png) [@Bongmaster](https://boards.straightdope.com/u/Bongmaster)\ **Post date:** [July 11, 2003, 7:50pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/19 "2003-07-11T19:50:35Z")
> [@](#): > > \*Originally posted by Derleth \* > \*\*We are experiencing _catastrophic breast failure_! Say again, we are experiencing catastrophic breast failure! The nipples have broken free from their moorings and are leaking Half-n-Half. Structural integrity is decaying rapidly. Initiating Operation Band Name! > > 😃 \*\* \*\*Derleth[/], where do I send the bill for my now coffee covered keyboard and monitor? ROTFLOL! ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [July 11, 2003, 10:10pm UTC](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748/20 "2003-07-11T22:10:20Z")
> [@](#): > > \*Originally posted by Duckster \* > **But will they come out with a video game for women where the men are naked and their scrotum and penis dangles in the breeze, as well as perk up when aroused?** Not likely. For whatever reason, images of naked sexy men just don’t seem to attract the attention of women as much as as images of naked sexy women attract the attention of men. Plus, video game consumers are overwhelmingly male. [Next page](https://boards.straightdope.com/t/modeling-physics-of-heaving-bouncing-jiggling-swaying-video-game-breasts/178748.md?page=2)