Tornado – FX

Task: sim and render of the elements tornado, debris and rain.
Software : Houdini 14
Technique : I’ve used a point distribution animated procedurally to generate velocity and density source fields to drive a low res smoke simulation. In order to maintain the simulation art-directable , at every time step I’ve replaced 95% of the simulated velocity with the source velocity. The resulting low res sim is fast (~1 fps). All the details of the Tornado have been added at render time using a volume procedural shader, which allowed me to advect the original low-res density along vector noise fields mixed with the velocity field itself.
Debris , Debris Skirt and Rain are particle simulations.

7up – Commercial

Client : 7up
Studio : Framestore LA

 

Work : CG Crowd.
In this project I had to create and place a crowd (3.000 to 2.000.000 depending on the shot camera position). Each agent was wearing a wristband that would emit light of different colors according to animated patterns. The pattern had to be clearly visible from a distance, but at the same time, the crowd had to be believable from a relatively short distance (~40 m). The Director wanted to see light interaction on the crowd for the light generated by the wrist bands.

In order to be able to work quickly and allow the compers to test different wrist band patterns in Nuke without re-rendering from Houdini, I choose the route of re-lighting the crowd in Nuke, rendering every necessary AOV from Houdini.

I was provided with a library of dancing CG characters and a set of textures for the clothing.
The system was subdivided in 3 steps:

  • Crowd generation : generation of about 50 characters, procedurally dressed using the textures provided (Houdini OTL). Additionally for each character I was generating data that would later help me to render AOV passes related to the wrist band position and light interaction range.
  • Crowd render per Shot : in each shot I was positioning the crowd painting points over a surface. Later I was using copy SOP (with Packed primitives packing option enabled) to instance the characters on the crowd. For each shot the crowd was rendered with several AOVs.
  • Nuke Relighting Setup per Shot : I set up a key Nuke setup in which the crowd could be relighted using P and N AOVs. Using additional AOVs containing the wrist band data, compers were able to replace the wrist band pattern procedurally in Nuke.