3D conversion : Converting a 2D film to stereo 3D is labor intensive and requires skilled visual effects artists to create a final result that looks natural. Creating two separate images from a single frame requires subtle adjustments to the viewing angle for each element in the image.
The process starts off with rotoscoping – manually cutting elements out of the image and then assigning them depth values to make different parts of the picture seem closer or farther away. These depth values allow the artists to reposition each element for the right and the left eyes. Once in place, the missing details for the left and right eye images need to be ‘painted in’ frame by frame.
“Stereo conversion is as much an art as it is a science, so we look at every shot individually and approach it in a handcrafted way”.
Hairy problem : Several shots in the opening sequence included very fine elements, such as hair blowing in the wind. “The Ollivander character is a wise old wizard with wispy hair,” said Dennis Michel, VFX supervisor. “Hair is an interesting challenge for any kind of visual effects work. For this film we had a small team of artists painting and tweaking individual strands for some time until we got the stereo 3D just right.”
The tools: For rotoscoping and reassembling the images, the team at I.E. Effects usesThe Foundry’s Nuke compositing system along with a set of in-house proprietary software tools that drive the workflow and link the company’s two locations. “We use automation to expedite the steps in the process, but this kind of work always comes down to the artist’s eye and a lot of patience.”
Read more on this in Below The Line.