CGSociety :: Production Focus
9 June 2009, by Renee Dunlop

Shake the hand of Rhythm & Hues (R&H), or all eight hands if you dare, for bringing the octopus in Night at the Museum: Battle of the Smithsonian to life. It was one among many of their characters in the film. Some, like the Lincoln Memorial and the Einstein bobbleheads, required the stone faced look appropriate for, well, a character made of stone. Additionally, R&H did set extensions and 2D work, 530 plus shots over the course of nearly a year that made it into the film. But if you want to embrace a character that will embrace you right back, look no further than the octopus.

OCTO INTRO
VFX Supervisor Raymond Chen described the octopus, roughly based on the Giant Pacific Octopus, as “eight arms with unlimited degrees of freedom, one of the most complicated rigs we’ve ever had to build.” The filmmakers went through many iterations on how it was to perform, complicated even further when, after viewing the previs, R&H realized it needed to stand up to scrutiny at full to medium frame, with some extreme close-ups, for most of the forty-four shots. “We did a fair amount of displacement map work to get very fine detail from pore level to macro. The texture is made up of large cellular shapes, so a lot of this is done through displacement mapping adaptive process, so close up we could displace to a greater tolerance and have more geometry.”

Yet this bundle of arms with a head had almost no facial features. “We needed him to be expressive,” explained Chen “but there is no actual face on an octopus. There are eyeballs on either side so the area between was used as a brow surface. A nose was implied in the center.” How did they manage to get expressions from a character with no face? “A lot of iterations. We had our animators do what they’re good at, trying to tell the story with body motion, timing, whatever expression we can get out of the eyes, for sure, but some of it is just about framing and timing.”

LOOKDEV
Finding the right balance of attributes to make the flesh of a sea creature out of water fell to LookDev artist, Dante Quintana. “We spent considerable time planning the layout of material groups and UV's. In order to limit textures from stretching and to prevent seams, we maintained a consistent scale from the tips of all eight tentacles, upwards throughout the entire body and into the mantle. We also kept in mind the workflow of our texture painters, Nick Cosmi and Jennifer Stratton, to ensure they would be able to manage what came out to be over 380 material groups and over 3700 individual texture maps. It was a huge undertaking, not only to obtain a photo realistic look that matched the concept art and feel of a Giant Pacific Octopus, but to also manage the thousands of texture maps ranging from 1k-4k resolutions.” Maxon BodyPaint and Adobe Photoshop were used to create the layers of images, details, and procedural textures. The outer skin consisted of over 100 Photoshop layers to generate textures of color, specular, subsurface, and displacement maps for the octopus in both sick and healthy versions.

To help achieve the feeling of depth and realism, Quintana’s team used subsurface along with a skin-slide technique and various levels of subsurface, allowing for different levels of light transmission. Thinner skin such as tentacle and gill edges and the suckers allowed more light through, while the body and head revealed veining details underneath. “The skin-slide provided a look of a main body inside moving slightly independent of the outside skin,” said Quintana. “The outer skin consisted of multiple layers of 8/16-bit displacement maps, created in Photoshop, and 32-bit displacement maps generated in Mudbox, ranging from the bumpy skin and veins, to the smoother tentacle bottoms, and the ridges of the suckers, to the wrinkles around the eyes and gills.”