Date: Sat, 6 May 2023 16:46:02 +0200
From: Paul Hertz via NetBehaviour <[email protected]>
To: NetBehaviour for networked distributed creativity
<[email protected]>
Cc: Paul Hertz <[email protected]>
Subject: Re: [NetBehaviour] Disaggregate Flocking?
For sure the behaviors of actual birds are far more complex than those of
boids. Similarly, L-systems model the growth of plant forms, but they truly
do not capture the way growth happens in plants.
Nevertheless, the simple models give rise to complexity, and their dynamics
might model something like a catastrophe inflection point. Some of the
sudden shifts you mention seem to me like a parameter of flocking behavior
suddenly changing value. I.e., coherence is suddenly greatly reduced,
large-scale flocking is absent, there's some local alignment, and above all
birds try to keep their distance ... as though failure to keep distance
precipitated the sudden drop in coherence? But that would be an image within
a simulation, not really an explanation of the dynamics of
food/mating/crowding, etc.
// Paul
On Sat, May 6, 2023 at 2:54?PM Alan Sondheim via NetBehaviour
<[email protected]> wrote:
Hi Paul!
These are absolutely beautiful! I've been familiar with boyds for a
long time and refreshed my memory before I did the piece. I don't have
the skills to implement the work, but what I was interested in was
probably closer to catastrophe theory (or what's left of catastrophe
theory?). The aggregates were rougher; the cormorants played a role,
and what was interesting was the sudden ragged shifts - all the gulls
in one section between bridges took off, then a few seconds later, the
next section etc. Or part of a section. But the pattern always
appeared chaotic, not like wheeling pigeons or starlings for example.
I was interested in what the birds were doing - they often dropped out
and the patterning was often indiscernible, as were the flock
boundaries - to the extent that it was unclear if there was flocking
at all, just birds in the air over an area. So I wonder whether
they're not reacting to a different form of coordinate system. The
cormorants by the way do flock in a traditional pattern, but the gulls
seemed more like Mandlebrot's percolations...
The menhaden migration - literally billions of small fish, many of
which die for lack of oxygen and coat the shoreline - was larger than
usual because of the dredging. So the birds were coming in "from all
over," enough to make newspaper articles. And the gulls were "forced"
into aggregates because the river system is narrow. There was enormous
squabbling over water territory (i.e. the water surface occupied by a
gull). It was strange as gulls and other birds also tried to flee at
times; this was going on for at least a half mile out into the bay.
I'm not sure the boyds model applies here since the crowding and
jostling was largely incoherent, the closer the gulls got to the
surface. I think a second interruption was mating rituals, since that
seemed to be going on as well. The birds were on edge, I think, not
used to this kind of crowding - a short interval in the video shows a
serious fight between two starlings, in which one was almost killed
(and was wounded); that's the first time we've seen that here before.
A lot of the time we couldn't figure out what was going on. -
I remember the game of Life of course, and "animals" in turbulence
(static formations in moving water, but the term might be outmoded
now).
Your images and videos are amazing!
Best, Alan, and thank you!
On Sat, May 6, 2023 at 5:43?AM Paul Hertz via NetBehaviour
<[email protected]> wrote:
I think some of my flocking images might interest you, as
might the code behind them. I implemented Craig Reynolds'
Boids Algorithm building on code by Daniel Shiffman. I
wanted to use the simulated flocks for drawing, not unlike
your multiple image bird paths.
Flocking and steering algorithms commonly use 3 or more
parameters. Separation, alignment, and cohesion are the
principal ones, to which field-of-view and other variables may
be added. Separation refers to the minimum distance between
boids, alignment is the tendency to face the same direction,
cohesion is the distance over which flock cohere, and
field-of-view is the forward-facing angle within which boids
"see" other boids. Field-of-view can give rise to V-formations,
so it's an interesting addition. I didn't use it in my
implementation.
Tweaking the variables (and their variability) can give you
vastly different behaviors, Boids with low cohesion distance and
large alignment distance have trouble flocking, for instance.
They make very tangled paths and never form a cloud of boids
moving in the same direction. Much of the variation you're
suggesting could happen within a simulation, just by varying the
parameters.
Here's a selection from the first series I created:
https://flic.kr/s/aHsjzxxd6B. "Land Lines" is an homage to
Colette and Jeff Bangert, pioneers of algorithmic art.
A later series, https://flic.kr/s/aHskAU7qF2, used video
tracking to move the boids. The code allows you to wave your
hands to move the boids, or you can point the camera at traffic,
to capture the flow, or whatever. I installed it in a gallery
pointing at foot traffic in the Chicago loop back in 2016.
Here's an example: https://vimeo.com/42786680.
The code for the version with video tracking still works on my
new MacBook, so it might be worth a try:
https://github.com/Ignotus-mago/Flocking. If you want to try it
out, I can help you with the installation.
// Paul
The first series
On Fri, May 5, 2023 at 5:14?PM Alan Sondheim via NetBehaviour
<[email protected]> wrote:
(might be useful re: Finsbury Park?)
Disaggregate Flocking?
https://youtu.be/R-J_KZI3dvY video
Rather than swarming or flocking behavior, I'd like
to call what
I see in these images aggregate behavior or
disaggregate
behavior - what I mean is that the behavior is
largely random
that the gatherings are very crude and so very
loosely bound
that they fall apart constantly; they are "somewhat"
incoherent.
I wonder if instead of an overall flocking behavior
algorithm
algorithm one might consider or one might think
about the
possibilities of local geodesics that each bird
follows that
would have some relationship to avoidance behavior
and to
coagulation behavior but at the same time would not
call this
one way another into an overall shape such as you
get with a
murmuration or migration flocks . These things are
much more
loosely bound if they're bound at all with the goals
in the
images when you look at the time lapse material.
When you look
at the time lapse material you can see that they're
much more
individually moving then usually would be found In
flocking
behavior. If anything they're much more loosely
bound by the
external circumstances of the edges of the water
body or bodies
. But the movement seems to be slightly circular and
that might
be the result of flight patterns that are necessary
to catch the
air and move properly in relationship to the other
birds to the
neighbors but it might also be almost random and
simply based on
avoidive behavior and looking for geodesics not
quite stop that.
[that is, aggregative behavior within circumstances
dictated by
neighborhood features such as trees, pools, rivers.]
Not looking
for geodesics but as if they were following highly
localized
coordinates of some sort. I'm dictating this, which
is another
sort of flock behavior in the sense that the words
are being put
together with some kind of semantic continuity that
the machine
is interpreting. But at the same time there are
withdrawals and
things are much looser then that. In this sense the
text itself
is a kind of aggregate that veers off in one way or
another.
What was most amazing was when all of the all of the
gulls took
off simultaneously or roughly simultaneously not in
a wave not
even in a loose flock but from the bridge to the
place where I
was making the recording. More than that, there's a
series of
bridges and a farther bridge which is difficult to
see in the
video they also took off at the same time there must
have been
at least 1000 birds in the river between the two
bridges and to
further bridges that were even beyond those two. I'm
fascinated
by this and have spent a considerable amount of time
trying to
figure out what's going on. Ironically it's a lot
easier, easier
to figure out with the murmuration or sandhill
cranes for
example or migration in V shape patterns in general
. But this
seems different seems a different kind of behavior
and the
disorderliness may in fact be incredibly deep which
would be
really fascinating . Patsy disorderly oneness might
in fact be
incredibly deep . That is disorderliness might in
fact be
incredibly deep. It's the same with this as it is
with the
flight of these birds errors appearing everywhere in
the text
the text bearing off and then coming back just as
the birds will
land somewhat in the same places that they took off
from
somewhat in the same area at least but individually
it becomes a
real headache to try to I sect what's actually going
on period
to try to sense what's actually going on.
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