Confetti Cannon Particle Effect

The first thing we learned in 3D Visual Effects was how to set up a particle simulation in Houdini, so naturally a particle effect was our first big project. I chose to replicate a handheld confetti cannon.

As with any design project, step one was gathering reference images and footage so I could study the way the confetti fluttered in the wind. There were plenty of videos online of people setting off confetti cannons, but one of the benefits of my subject was that I could buy a dozen of them very cheaply at Walmart and collect my own references for the assignment. My friends and I got together and set off a lot of cannons in the parking lot of my apartment building to get videos of the explosions from a lot of different angles, which had the added benefit of letting me see the confetti clouds in person. I didn't just have to rely on matching my video footage, I could also use my own memory of the experience for the effect.

Modeling the cannon wasn't strictly necessary for this assignment, but I like modeling things and this was too good of an opportunity to ignore with the real-world cannon sitting right next to me on the desk. Plus, building the cannon to-scale helped me make sure the confetti cloud was the right size later on.

From there the effect was built in Houdini with particle emitters set just inside the cannon's barrel. The final effect had seven emitters to give different sections of the overall cloud varying speeds and wind currents, and this early render of the effect makes it easy to see three of the biggest groups.

Once I was satisfied with the way the cloud was shaped and how long the confetti was hanging in the air, I was able to replace each particle with a single piece of confetti. Pink, yellow, green, and blue pieces were evenly distributed through the cloud by using a simple VEX script to pick a color based on each particle's ID number.

The final version of the effect was rendered with motion blur. I probably spent the most time on this project just adjusting the timing of each of the particle emitters. Even though they all fire at once, each part of the cloud needed to hang in the air for a different amount of time to make the effect look good. Some hit the ground early on, some went all the way up or all the way to the side, and it was a bit of a balancing act to make sure the cloud's relationship with gravity looked natural.