SideFX - Pyro COP Experiments

Year: 2025
Client: SideFX
Discipline: Pyro Simulation / R&D
Role: Marketing FX Artist (Intern)

A rebuilt POP curve force shapes a tornado velocity profile: strong pull near the ground, easing off at the top

Density and temperature driven by rest-space noise, so the patterns lock to the motion

Fire is sculpted, not simulated: rest-space noise with a vertical ramp that scrolls over time

Relative density: how crowded each point is, thickening and thinning frame by frame

In Pyro Bake Volume the fire locks into the smoke and follows it, though it was never simulated

A Geometry Light: the fire’s colour drives the light

Volume velocity scale pushes the sense of speed

Blurred velocity runs the motion straighter, without the default swirl

Pyro Turbulence, masked by temperature and density

Pyro Disturbance adds random direction to the velocity

BFECC advection: slower than Advect + Sharpen, with clearer detail

A custom colour field built in SOPs from the source’s trails

The colour field living inside the COP sim, previewed with Pyro Bake Volume

During my internship at SideFX I spent much of my time on the new Pyro solver in Copernicus. Unlike the classic DOP Pyro, it is written in OpenCL and runs sparsely on the GPU, inside the same image network as everything else in COPs: a source can be built there, or brought in from SOPs, and the simulation runs live while it is being changed.

Because it is so fast, I could treat smoke the way I would treat an image. The same small explosion took about five seconds in COPs against thirty-eight in DOPs; a low-resolution version of the colourful explosion cooked in about nine seconds against five minutes, and the full version reached about a hundred and twenty million active voxels. Blur, blend and max operations from the image toolset shape the motion directly: blur on velocity reads as viscosity, and blending velocity by length rather than per axis keeps the strongest push in any direction.

The fire tornado took about a month. A custom curve force shapes the particle source into a tornado profile, the smoke is held together with axis suction, and the fire is not simulated at all: it is sculpted from noise and relative density, then baked into the smoke so it follows the same motion. I presented the work at Houdini Equinox in Toronto, and the setups are available in the SideFX Content Library.