The lava, of course, was an integral part. There were not only different setups but also different scales, ranging from a wound on Zeus' arm to the wider flow linking the main island to Kronos. The setups were created in Houdini based on a basic procedure, but the individual looks and speeds were determined for each scale. The approach was to use minimal simulation to drive the art direction (textured sculpts) in keeping with the more grounded vision of the director.

There were three phases to the setups and required various tools: one tool fractured the mountain based on a map and created the volumes inside; the initial animation was done by hand and then this was used to art direct the remainder of the simulation, which broke the rocks into smaller pieces and finally into a fluid. This was achieved with particles. On top of that, were smoke, dust and debris.

Dumont points to three challenges: setting up the lava and pyroclastic workflows and getting the scale right. The most difficult shot was the draining of the lava from Zeus to Kronos. This required all the setups working together, replacing the environment with a CG one and re-projecting the characters and blending together the different lava setups and adding the atmospherics.

"I think this was the biggest project we've had in terms of its complication," Dumont concludes. "We achieved a good thing for this process and we developed our pipeline based on that. And also we developed some tools that are very interesting for the Kronos animation."

Bill Desowitz is former senior editor of AWN and editor of VFXWorld. His blog is Immersed in Movies (www.billdesowitz.com), he's a regular contributor to Thompson on Hollywood at Indiewire and he's the author of the upcoming James Bond Unmasked (Spies), which chronicles the 50-year evolution of the iconic superspy from Connery to Craig.