Letting the Predator Hounds Loose
However, Hybride and Ubisoft Digital Arts collaborated on the CG Predator Hounds, which controlled by the Predators to flush out their prey much like a fox hunter uses its hounds. Hybride and UDA not only handled the Hounds but also moments when the Hounds interact with the jungle environment. Hybride artists replaced real leaves and debris during shooting with their own CG greenery.
"These are like Hell Hounds: very mean and nasty, so, of course, they were built and textured in CG and we had to integrate them into the plates of the live shooting," explains Philippe Théroux , lead CG supervisor for Hybride. "Sometimes the guns on their shoulders were animated in CG; the blade of the Predator was sometimes CG." In all there were 470 shots.
Hybride was provided with designs for the Hounds from Troublemaker, but the large, protruding horns proved problematic when hunting their prey, so a little tweaking was done in consultation with the director. For the Hounds, Hybride used ZBrush and Softimage and they had to be photoreal.
"The challenge of the Hounds was the same kind of problem you have when animating an outer space creature that doesn't exist. It was striking a balance between a heavy, mean look but having the ability to also move swiftly. So we had to be careful that they didn't look too light when they jumped to take a human down."
According to Daniel Leduc, Hybride's visual effects producer, the CG jungle was the biggest challenge because of the interaction. "We had to have those quadrupeds run in two paths that were covered with dead leaves," Leduc suggests. "So to have those leaves moving or being pushed or flying around as the Hounds were running was a challenge. In all of the shots, we recreated the path entirely in CG and did a simulation of the dead leaves and twigs that were on the forest floor. The simulation was done with ICE and the render in XSI with mental ray.