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birds
November 2009 
It's for the Boids
Posted on Jun 2nd, 2009
by 
Meenakshi
Meenakshi
While looking for a quote on a flock of birds today, I came across articles on how Craig Reynolds studied the flocking behavior to design computer models that have been used in movies such as Batman Returns, and who knows what else! [I hope some of my friends will point me to other applications]
And I thought only Bugs Bunny called birds - 'boids'!
As I read Craig's article, it seems to me that boids can easily be used to describe online communities. Well, not easy for me, but perhaps for the scientists attracted to Dale Husband's Universal Science Forum ? I'm heading there now.
Excerpts
The basic flocking model consists of three simple steering behaviors which describe how an individual boid maneuvers based on the positions and velocities its nearby flockmates:
:
"Each boid has direct access to the whole scene's geometric description, but flocking requires that it reacts only to flockmates within a certain small neighborhood around itself....Flockmates outside this local neighborhood are ignored.
Video based on his work:
And I thought only Bugs Bunny called birds - 'boids'!
As I read Craig's article, it seems to me that boids can easily be used to describe online communities. Well, not easy for me, but perhaps for the scientists attracted to Dale Husband's Universal Science Forum ? I'm heading there now.
Excerpts
The basic flocking model consists of three simple steering behaviors which describe how an individual boid maneuvers based on the positions and velocities its nearby flockmates:
 | Separation: steer to avoid crowding local flockmates | |
 | Alignment: steer towards the average heading of local flockmates | |
 | Cohesion: steer to move toward the average position of local flockmates |
"Each boid has direct access to the whole scene's geometric description, but flocking requires that it reacts only to flockmates within a certain small neighborhood around itself....Flockmates outside this local neighborhood are ignored.
The boids model is an example of an individual-based model, a class of simulation used to capture the global behavior of a large number of interacting autonomous agents. Individual-based models are being used in biology, ecology, economics and other fields of study.
Note that the straightforward implementation of the boids algorithm has an asymptotic complexity of O(n2). Each boid needs to consider each other boid, if only to determine if it is not a nearby flockmate. However it is possible to reduce this cost down to nearly O(n) by the use of a suitable spatial data structure which allows the boids to be kept sorted by their location. Finding the nearby flockmates of a given boid then requires examining only the portion of the flock which is within the general vicinity. "Video based on his work:
The Original Minds Eye - Breaking The Ice (Love Found) (Stanley &
Access: Public
The sun it shines, the grass has riz
-I wonder where the boides is?
:o)
A delightfully mind bending article, my friend.
really interesting!
Beautiful and poignant… how does one decide who is NOT in one's local neighborhood? doesn't the individual have the opportunity to be more expansive (and inclusive) than the others in his/her 'local neighborhood'? the video seems to suggest just that… and i love it!
I usually react only to flock mates in my general vicinity… I can handle a few 'boids' at a time, the rest get to do their own thing!
Smiles!
amber
Well, as long as I'm in your general vicinity, Amber, I'm fine with that! And didn't you laugh at Dave/Tharlam's fun verse?
Hi Nicole, thanks for leaving that beautiful smile here. NISHTHA- you're back!
I think that the local neighborhood isn't something one decides; but something that one gravitates to. In other words, whoever we're interacting with daily, is immediate neighborhood; weekly, a little further away, monthly even further ….and so on till we reach those we don't interact with at all.
But I'm not sure if there's a way of incorporating depth of interaction - not frequency - to this model. any ideas?
Your blog gives me something to think about, I might come later with other comments… very interesting indeed :)
Cool!
Hey Meenakshi…I OWN the Mind's Eye…the video you posted, Breaking the Ice, is my MOST favorite clip in the whole series!!! I soooooooo love it, still gives me goosebumps…there…I mentioned a bird LOL :-D
“However it is possible to reduce this cost down to nearly O(n) by the use of a suitable spatial data structure which allows the boids to be kept sorted by their location.” yeah, but what if that boid over there decided it wanted to target the bald guy … you know, if i was a boid, that would be a reason to make 0(n) just a simple O (as in “oh yea, baby!”) and the (n)s would have to fend for themselves!
Interesting mind food this a.m., thanks for the links!
Boids are neat, how kewl is that ? ;-)
The Dance of Many as One is waaaaay more than kewl, Lars =)
I recently discovered my 'general vicinity' touches everything on this planet and beyond no matter how separate I think I am from it all. So Meenakshi, you are in my general vicinity every moment I take air into my lungs and am not feeding my carcass to the scavenger boids! Maybe even then…
I did laugh at the clever verse David gave us and I believe he's one of the boides in question! The rest of us boides are giggling behind him whilst he wonders!
Hmm..I could've sworn I replied to you, Ariela. Wonder if there are thought boids- did your thought boid come close to my thought boid ? ;p [Picking up from Amber]
I love those starlings, Lars!
now I can tackle business voodoo's
“yeah, but what if that boid over there decided it wanted to target the bald guy … you know, if i was a boid, that would be a reason to make 0(n) just a simple O (as in “oh yea, baby!”) and the (n)s would have to fend for themselves!”
I think translocation is possible!
And maybe even apparating [apparition]?