Riders Shot 10_0080 FX Breakdown

Now that animation has pretty much been finalized, I’ve been spending time on getting more FX complete. This is mainly comprised of doing dirt and particle trails, mixed with some pyro here and there.

Here is the first FX shot I did for the film. I used the process I learned in this shot for most of the other trailing shot. I’ll break it down layer by layer.

Burnout

The first thing I tackled was the sourcing for the pyro.

First, I isolate the tires and scatter points along them. Its important to use a pointdeform and attribute interpolate to keep the scattered points in the same place as the tire rotates. This is important for grabbing the velocity and the POP simulation later.

Next, points are blasted based on their distance to the ground. This is fed into the POP Network where I source particles from. I found this sourcing technique in a John Kunz video.

POP Setup

Result

Points are given density based on their age and noise, then they are fed into a sparse pyro simulation

Inside of the pyro sim. I use a lot of gas reduce and modifying data to grab the max values of the speed and density to control the disturbance and turbulence. This is the result.

Dirt Sim

For the second layer, a similar setup for the sourcing is used, except this time I used the Axiom solver for the sim instead of the sparse pyro solver. At the time, I was curious on how Axiom performed differently than Houdini’s pyro solver and I thought it would be a good opportunity to try it. The particle sourcing is similar, just changing a few parameters around to better fit the simulation.

Here’s the result:

Iterating quickly was a lot faster with Axiom, thanks to the GPU acceleration, and I was able to get a satisfactory effect quicker than I would have using the sparse pyro solver.