Practical Elements Enhance Visual Effects In "Oz The Great And Powerful"

The Kansas native behind the visual effects in movies including Spiderman I, II and III knew taking on the beloved world of Oz would be an enormous responsibility.  In learning Walt Disney was going back to the source material; the world crafted by author Frank Baum in 1901, Stokdyk was intrigued.  When he discovered Sam Raimi, who he worked closely with on the "Spiderman" franchise, was directing, he enthusiastically signed on.

"I'm excited to do anything Sam wants to do," said Stokdyk.  "He offers so many visual choices; he is just such a great director.  This story of Oz has been kept alive over the past 100 years - I was really excited!"

Bringing Oz into the digital age took two and a half years and an very classic approach: physical sets.  Raimi wanted to evoke as much emotional depth from his actors as possible, and felt a classic, working stage would enhance the story.  Stokdyk worked closely with Raimi and production designer Robert Stromberg to flesh out landscapes, buildings and designs highlighted in Baum's books.  While Stokdyk was confident in a seamless integration between the physical sets and the digital enhancements, he was more concerned about the matching the effects to the native stereo 3D capture.

"It takes longer for CGI; it's much more difficult in regards to matching," said Stokdyk.  "It does impose discipline and decision making.  Everyone does pay attention more."

In addition to layering effects over practical sets and incorporating 3D elements into the mix, Stokdyk also had to find a way to bridge motion capture characters such as the China Doll and the Flying Monkeys with the lead human characters.  Raimi wanted the actors to interact as much as possible, however it was unrealistic to expect actor Zach Braff, who plays a flying monkey, to hang from cables to maintain eye levels throughout his scenes.   Reflecting on his experience as VFX Supervisor on "G-Force," Stokdyk recalled the emotional response and gentle approach the actors had when they held a real guinea pig as opposed to the stuffie stand in used during shooting.   He came up with an idea that surpassed a stand-in monkey that allowed the CGI actor to interact with the rest of the cast while eliminating the spacial and technical challenges motion capture presented.

Stokdyk built a soundproof room off set that was rigged with a camera and audio recording equipment.  An actor would sit inside the room and his image and dialogue was projected through a monitor attached to a puppet rig held at the correct eye level.  For flying monkey “Finley,” Zack Braff was able to fully interact with his co-stars without engaging in physical stunts including balancing on a fence, or flying six feet off the ground.  In the case of the China Doll, early discussions revolved around using the puppet in the final film, however with such stylized visual effects, the puppet’s expressiveness was extremely limited .

While the puppet cam helped resolve some of the key challenges of creating believable scenes between actors and CG characters, the second largest challenge Stokdyk had to overcome was the interactions between characters and effects animation.  One example of this is the Magic Fog found in Oz.  Because there is no equivalent substance that can be studied and tested, a considerable amount of trial and error occurs when blending the substance into the scene.

“In the case of the Magic Fog, it has to react and interact with all the different characters and species,” said Stokdyk.  “You watch the scene and see the results, then modify the characters accordingly, which also means you have to modify the effect to interact with the change as well.”

While Stokdyk enjoyed every aspect of the shoot, from blending visual effects with the practical sets and pushing the saturation levels to elevate the vibrant colors of Oz, to finding new ways to introduce CG characters with real actors, to enhancing effects animation in a 3D world, there were a few stand out elements he’s particularly fond of.  He loves the lighting his team created for the baboon attack, he’s proud of the design and softness they captured in the China Girl character, and he feels the “bubble voyage” is one of the best 3D sequences he’s worked on.

“It’s a nice 3D sequence, a beautiful showcase of bubble dynamics and effects,” said Stokdyk.  “It’s really gorgeous and a great example of the environment work Imageworks is doing.”