The original 1981 release of Clash of the Titans will forever remain a classic thanks to the stop-motion work of special effects legend Ray Harryhausen. In 2010, this tale of Greek Gods and Heroes was updated with stop-motion creatures being replaced with CG animation. One key advantage of going digital was the ability to add realistic dust and debris to anchor the creatures to their environment and make each shot more believable.
Leading London-based visual effects house Cinesite played an instrumental role in bringing modern technology to this classic tale. With Houdini by their side they brought to life the monstrous, scorpion-like creatures called the Scorpioch. This was accomplished over the course of 176 shots. Cinesite refers to their work in the new updated Clash of the Titans as some of their most creative work to date.
With the main Scorpioch sequence, Cinesite would need to combine live action plates with CG creatures which had to seamlessly match the photographic plates. Houdini was their go-to tool for the visual effects in these shots.
Dust and Debris
In the Scorpioch battle sequence, the giant creatures kick up intense dust and debris during battle. In the initial stages on the set in Tenerife the crew found that as they walked around their footsteps released much more dust than they had initially anticipated. For the movie, digital dust and debris would need to be created with a combination of particles and fluids. Access to Houdini’s dynamic micro-solvers gave Cinesite a lot of control over the fluid simulations which gave them the confidence to get exactly what was required out of each shot.
For the desert shots, the character movements were really fast and dynamic and therefore Cinesite needed to transfer character velocities into a volume to achieve accurate results. The volume was then sourced into the dust fluid simulation. When each foot of the giant Scorpioch collides with the ground, it emits particles. These were used as an emitter in Cinesite’s custom Smoke tools and were then rendered as instanced geometry.
After each simulation was completed and rendered, sand point particles were emitted from the same gravel particles and set up to flow through the dust velocity field. The Scorpioch’s foot collision was also used to deform the ground geometry in the shots where it is visible.
Creating Photorealism with Mantra
Photorealistic quality was imperative and the dust and debris created by the Scorpioch had to look perfect within the photographed plates. To add to the challenge, the scenes were shot under stark, daylight conditions. Every piece of FX work created by Cinesite in Clash of the Titans was rendered using Houdini’s Mantra renderer. They made excellent use of Mantra’s Deep Camera Maps to work with the smoke volumes and ultimately improve the realism in the completed shots.
Lighters working on the creatures rendered deep shadow maps from the camera’s point of view in RenderMan and then converted them into Mantra deep camera maps. These were then used as a holdout which picked up RenderMan’s motion blur and displacement which Mantra used to create the final rendered FX plates. This made it easier for compositors to bring creature work rendered in RenderMan together with FX work rendered in Mantra.
Customizing Houdini’s Tools
Taking full advantage of Houdini’s open architecture, Cinesite built custom tools for the job. Using microsolvers from Houdini’s Pyro Tools, Cinesite created a smoke fluid solver that they named csSmoke. With csSmoke in place, Houdini’s fluid solvers were then incorporated into the custom tool which dealt with the sourcing of fluid, low-res and up-res simulation, caching and shading. Although csSmoke was a tool created to be used in Clash of the Titans, it is now a tool that Cinesite can use on future projects.
Thanks to a talented and motivated team of enthusiastic Technical Directors along with Houdini’s open architecture and speedy simulation and render times, the team at Cinesite was able to get the job done as well as help in creating an exceptional update to a classic film
Cinesite Visual Effects Supervisor: Simon Stanley-Clamp