Concept
When I read thought about tension over time the visual that came to mind was that of a ball being squeezed until it ruptured. I originally wasn’t sure how I was going to fit that into the simulation and how I would incorporate flocking behavior but as I went through the the work of Robert Hodgin I had an idea.
I liked the look of the flocking behaviour in 3 dimensions as well as the red lighting. I thought about having it contained inside and that ball I had in mind upon rupture the flocks inside would escape rapidly and slow down over time.
Sketch
(orbit control is enabled, click and drag your mouse to view from different angles when viewing the sketch)
Highlight
function releaseBoids() {
confinementActive = false;
released = true;
releaseFrame = frameCount;
for (const boid of boids) {
let outward = p5.Vector.sub(boid.pos, centerPoint);
if (outward.magSq() < 0.0001) {
outward = p5.Vector.random3D();
}
outward.setMag(random(5.5, 8.2));
boid.vel.add(outward);
boid.maxSpeed = RELEASE_SPEED_START + boid.speedBias;
}
}
Once the circle reaches a certain threshold radius it vanishes and the function above is called. It’s only about 15 lines but in my opinion it creates the most interesting effect in the entire simulation.
What it does is simply give each boid an outward vector force of a random magnitude between 5.5 to 8.2. In my opinion that range and those values make it just right that the effect is not too strong that it’s overwhelming but is not too weak that its underwhelming but is instead in my opinion satisfying.
Milestones
The Humble Sphere
My first step after creating the WEBGL canvas was to make the sphere which decreases in size over time. I chose a black background to give the most contrast for any effects I add later on. For the sphere I chose a light-blueish color mostly because of personal preference. The color of the sphere itself is not meant to have much meaning instead I want the attention to be on the boids and the decreasing size of the sphere.
Boids
These are the boids travelling in 3 dimensions. At this point in time they did not have any special effects. I wanted them to be read since I imagined the effect of squeezing to be like that of increasing heat. In the real world particles as they are trapped in a volume that is decreasing increase the amount they vibrate by and the vibration also known as brownian motion is what we call temperature. It’s how combustion occurs in diesel engines whereby the volume decreases as the cylinder compresses the fuel air mixture and unlike gasoline there is no spark plug the combustion alone is enough to combust (this is known as compression ignition).
Boids + Sphere
The way I had the boids stay inside the sphere at this point was by hard limiting the position of the boids rather than manipulating the steering direction as well (I implemented that as well later on).
Final
In the final I made a few key improvements. I added multiple gradients and made the blendMode ADD: The color of the boids change based on their speed, at their fastest they are purple, at their slowest they are red, the radius of the boids change based on how close or far they are to the center of the sketch, bigger towards the center and smaller towards the edges, lastly blendMode(ADD) meant that with more boids overlapping the colors get added and make a whiter color this makes it easier to see when boids are more clumped up together especially at the beginning.
Reflection
I’m happy with how the effect turned out and I was surprised by the swirling effect that came about in the beginning. As the circle decreased the boids still moved as they would normally albeit constrained and this made it look like they were swirling around the circle.
Hodgin’s work was made in Houdini which utilized the GPU and made the effect of using point lights possible with large amounts of flying objects whereas in p5 I don’t think the same would be possible and still retain a high framerate. I found that for my simulation around 600 was the limit for the number of boids whilst still running fairly well and that was without any lighting effects the best I could do was add the blendMode(ADD) line to make things more aesthetically interesting.
Going forwards I would like to try out different software maybe openFrameworks to see what is possible and also I want to try out audio cues for when the sphere vanishes and for boids that are travelling close to the camera and based on how fast they are going.