Radium | ReelFX - Katy Perry: Firework

Sexy, fun and flirtatious are words best used to describe pop star Katy Perry's music videos. In her latest video titled “Firework”, @RadicalMedia director Dave Meyers wanted to make a visceral change from Perry's previous videos. In “Firework”, the eye candy shifts from the voluptuous Perry to practical and computer generated firework effects.

Using Houdini, the team at Radium/Reel FX were able to create stunning photo-realistic fireworks that were used in conjunction with practical pyrotechnic effects. Like many Houdini users, Radium/Reel FX likes to get under the hood and leverage the openness of Houdini to create their own custom tools. Doing this, they constructed a highly flexible “Firework” tool.

The initial design for the firework tool allowed it to generate pyrotechnic-like effects that would replicate anything from a simple bottle-rocket launch to a more complex blossoming explosion where many events are taking place.

Twelve Houdini Digital Assets were created from the ground up using Particle and Surface Nodes. Essentially, the tool focuses on particles and rendering. These assets all worked in conjunction with each other and provided them with a single interface that had all the rendering and controls already built-in allowing the artist to focus simply on the task of creating.

The Firework tool also had to be expandable as to allow further assets to be integrated into it when necessary. In the later stages of production they would add a custom curve tool that allowed them to visualize every firework launch and its timing before having to simulate. Being able to bypass the simulation sped up the process immensely.

Custom Python scripting was employed to control the rendering for the shots. Through Python they were empowered to be able to automate rendering and additional frame buffer support to allow a single image to hold 15-20 additional layers.

Having this render control allowed for the artist to control a large variety attributes after the simulations were cached. This allowed them to do such things as dial-in things like point size, velocity and super motion blur streaks that they rendered as lines instead of particles.

The final product was assembled using Flame and Nuke to composite the computer generated effects on top of the pyrotechnics that were captured onto live plates. All of the final sequence shots in the video at Buda Castle showing fireworks in the air or launching from people were created with the Firework Tool.

Almost any CG smoke, particle, procedural geometry modeling or altering is all done with Houdini at Radium/Reel FX.

Anthony Chappina, 3d Effects Animator remarks “We use Houdini for most of the FX work done in our entertainment and commercial divisions. Our main reason is the robust pipeline it allows and that you never end up working backwards”