The work provided by Luma, which now spans two studios worldwide, begins with one of the most iconic aspects of L. Frank Baum's chronicles: the tornado which carries the central character to the distant and magical land of Oz. Luma also provided a variety of other effects including earth-to-sky landscape creation, full CG costumes, vehicles and magic effects.
The tornado would be Luma's heaviest lifting during the project, as "Oz The Great and Powerful" Visual Effects Supervisor Scott Stokdyk requested an exceptionally dense particle and fluid simulation for the effect.
"From the beginning, for shots taking place inside of the tornado, Scott wanted to see a tornado density that was primarily made of very fine particulate; billions and billions of particles," said Vincent Cirelli, VP / Senior Visual Effects Supervisor at Luma. "Over the years we've built robust tools for partitioning and moving extremely complex data sets through the pipeline, so it was a challenge we were happy to undertake."
Luma's creation of Oscar Diggs' (James Franco) hot air balloon, hazardously flying debris, including a 3d calliope and a full earth-to-sky CG background, added depth and reality to the howling tempest in the full CG tornado scenes.
A bit of magic was also added to make Glinda the Good Witch a bit more glamorous. Utilizing a complex cloth simulation, combining varying cloth densities such as silk and cotton, Luma replaced her dress with a flowing gown throughout the film. The garment was rendered with their in-house, Arnold based cloth shaders, custom developed for "Oz The Great and Powerful."
In one of the films most dynamic sequences, Luma added a variety of magical effects to the epic battle between Glinda and Evanora. Their software development team created a suite of custom tools for generating the intense lightning and energy effects coming from the witches, dubbed LTree. These tools allowed artists to art direct thousands of branches of electrical energy on one side and pure light on the other. When the two forces collide, dramatic prismatic effects splinter off creating a visually stunning effect. Compositing TD Alex Kahn created the tools from a complex mix of volumetric lighting rigs and multilayered Nuke Gizmos in order to achieve the result.
"This film will take its place among other icons of filmmaking as a new chapter in a beloved story," said Executive VFX Supervisor and Luma Co-Founder, Payam Shohadai. "It was a pleasure to work on, and to have added our part to a project that is sure to be remembered."