As if a clash of the Titans wasn’t difficult enough to create, an epic battle involving Kronos and an assortment of mythological creatures was an even more “titanic” undertaking. Sorry. Couldn’t help myself.
MPC VFX Supervisor Gary Brozenich and Producer Oliver Money were up to the task, leading MPC’s team that delivered 280 shots that included the opening Dream Sequence, the Chimera attack, the final battle with Kronos, the Makhai warriors and Pegasus, as well as the Gods dying and dissolving. The team also worked on full CG temples, set extensions and a number of stunning DMPs throughout. Here’s a breakdown of some the main sequences:
Kronos, King of the Titans
One of the first challenges the team faced was to bring to life Kronos, father to Zeus, Hades and Poseidon and feared King of the Titans. Starting with a clean conceptual slate, MPC's art department decided to go back and explore Kronos within Greek mythology.
Understanding that Kronos was the Titan God of Time and Ages, the team chose this direction as a starting point and began to collect references and produce exploratory sketches based on this concept.
Through a number of initial images, the team explored various concepts, from a more elemental creature to a more human-like giant. Ultimately it was decided that Kronos should have a more human form to help reiterate the connection between him and his sons rather just being seen as a monstrous titan. The concept art team then expanded on some of their original ideas of using volcanic rock as a base, which provided needed context to how something could develop and grow over a long period of time. This concept formed the base of Kronos’ evolution.
Once the conceptual direction had been decided, a texture reference was created and used as a base for the 3D modeling and texturing pipeline, which could then be used as a point of reference for the rest of the team.
A variety of clay mixtures were created and painted onto the face and body of an actor which were then used as reference points by MPC's modeling team to help artists understand how magma and volcanic rock might move and fall around a moving object. The textures were also used for creating believable crack and displacement maps.
The task of creating such an important vfx-driven creature was formidable. MPC’s team was faced with the huge challenge of creating various behavioral effects elements, including spraying and flowing molten lava, crashing and cracking solid rock as well as atmospheric elements such as smoke and dust. As Kronos lays waste to the battlefield, two plumes of dense smoke trail behind him. One is connected to Kronos’ body with another following him. These were placed and layered to emulate Kronos’ movement stirring up a thick, dense eruption of smoke both from the titan and through the volcanic rock. Finally, live action smoke was incorporated to give an even denser and more realistic feel to the sequence. Scanline’s Flowline was used to simulate the smoke simulations. In order to handle the huge amount of data per frame, a new set of volume tools was created. In addition to the smoke plumes, Kronos also oozes and sprays different forms of lava from his surface. MPC’s artists created molten-to-cool lava streams using Flowline fluid particle simulations. Solid rock lava was made using MPC’s proprietary rigid-body solver, PAPI. Kali, MPC's finite element-based destruction tool, allows artists to shatter and destroy objects at render time. The program was used to handle the cracking and breaking of rocks, the trailing particles and to create fluid dust simulations and particles. The compositing team enhanced the sequences by adding further layers of dust elements on top of those.
The Chimera
Early in pre-production, it became apparent that the Chimera creature would be too large and agile for a man in a suit to handle. Consequently, the decision was made to use a full CG creature, requiring previs on a number of shots to provide the crew a geographical layout for the sequence. This helped the production designer create arenas where battles could take place with the actors, stuntmen and props going head to head in precisely mapped out spaces. The Chimera itself was largely designed in pre-production, then handed to MPC to recreate as a CG model.
The specific challenge for MPC’s rigging and animation teams was how to make a beast with two heads move in a realistic fashion. As Brozenich explains, “The trickiest issues involved where to place the split in the neck, how far back on his spine would feel natural and how to proportion the rest of the anatomy to compensate for this. We also had to gracefully handle the inter-penetration issues arising from two heavily mobile portions occupying the same anatomical space. Thankfully, both issues were dealt with very effectively and very early on with range of motion studies.” MPC’s animation team looked carefully at the animation of the Chimera, referencing material of lions hunting and attacking. The FX team handled the Chimera’s fire-breathing with a mixture of elements created using Maya and Flowline combined with actual flame thrower footage shot on set.
The Makhai
The Makhai are two-headed, double-torso, sword-wielding killing machines. MPC’s concept art department designed these vicious creatures, which were based on an initial brief from the film’s VFX Supervisor, Nick Davis. The creatures were to emerge from balls of burning volcanic rock surrounding Kronos, but were not supposed to be too strong or large to battle humans. Director Jonathan Liebesman’s vision of the Makhai involved multiple arms and two distinct torsos and heads. The challenge for MPC was not only understanding how a character like this could fight, but more specifically, how it would emerge from molten balls of lava, run and navigate through complex terrain while swinging swords. To visualize the dynamics of such a creature, MPC’s concept, rigging and modeling teams collaborated to create motion studies which led to a final design. Having two body elements meant that the rigging team had to focus not only on the creature’s anatomical structure but also on how the split double torso would affect the creature’s movement. Many design iterations and some very clever problem solving resulted in the final Makhai creatures seen on the screen.
The Gods’ Death Sequence
In the Gods’ Death sequence, the titans, thankfully, are turned into sand. Shots were match-moved and actors were roto-animated to their performances. The actual destruction process was created using MPC’s in-house tool for shattering and rigid body simulation, Kali. Once the ‘Kali effect’, which provided the gross collapsing effect, was approved, the system was used to drive a more granular particle simulation resulting in the sand-like appearance. Likewise, the initial model undergoing the Kali effect was used to spawn a surface of particles that inherited their color from the textured and DMP-projected geometry. This served as the rendered hard surface for the actor, which was then introduced in a ‘patchwork’ across each performer’s face and clothing by the compositing team using Nuke. In some cases, whole sections had to be re-tracked and warped to contend with the changing topology of their faces as they delivered lines.
The final battle required MPC to develop an enormous 3D environment, which was a combination of plates from two primary locations - Tiede National Park in Tenerife and a completely different looking battlefield location in south Wales. The initial eruption and Kronos’ path of destruction required several weeks of specific aerial photography over various volcanoes and lava-bed terrain in Tenerife. The plan was to use live action plates for all of it so the editor, director, supervisor and all of the artists had an inherently realistic base to work from that could be re-projected and altered significantly in post as required.
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Dan Sarto is editor-in-chief and publisher of Animaton World Network.