"In particular, the transformation scenes required a lot of fresh ideas, trial-and-error and custom work to get what worked for Joe," explains Valdez in a prepared announcement. The transitions broke down to six painful stages, including expanding veins and skin bruising, hair growth and the visible change of muscle and bone. Cyber scans of del Toro were used as the basis for a fully articulated head rig, capable of going from the actor to a fully transformed Wolfman. Custom animation setups were built for hands and feet as well, then groomed with MPC's proprietary Furtility software, offering the ability for custom hair work on a per shot basis, in order to bridge live-action shots and obtain a perfect match to shots of makeup and mask enhancement. Many of these shots were extreme close-ups, requiring detail down to every pore of skin. Skin lighting and shading were pushed to the next level for this project, including new efficient methods for sub-surface scattering and fine specular modeling.

Full London rooftop environments were also created, using a combination of 3D architecture and 2D matte painting. Several different Victorian-era environments were entirely designed at MPC during post, in addition to the master shots looking over the Thames River, and a time-lapse shot located under London's iconic Tower Bridge. MPC's location in central London has proved invaluable for creating such environments via photogrammetric modeling from location shoots.

The 2D team led by Arundi Asregadoo consisted of projecting photography onto animated Wolfman faces and legs, enhancing live-action work. Not surprisingly, transformation shots came together in compositing, where artists tracked in fine veins and skin changes, based on texture work generated by MPC's fx department. Atmosphere was a constant issue in the film, with compositors blending in many photographic elements as well as simulated smoke and debris. And compositors worked closely with environment artists in a collaborative effort, using MPC's techniques for multi-layered 2.5D environment rendering.

Meanwhile, Rhythm & Hues was called on for 150 shots, including some last minute adjustments; namely, having the Wolfman go from biped to quadruped. "This was something we hadn't explored before and we had to literally hit the ground running," Begg continues. "It was quite difficult to make look real, and, in fact, was the trickiest sequence of effects in the whole film. The transformation is one thing: you know that's coming. But to make a tall humanoid shape go from biped to quadruped is quite difficult because the proportions of the legs are very strange. I think Rhythm & Hues solved that aspect quite heroically."

"The issue of running on all fours was challenging in that people have a much different relationship between arms and legs than dogs do between their forearms and rear legs," explains Derek Spears, visual effects supervisor for Rhythm & Hues. "The dogs' limbs are the same length and our legs are much longer than our arms, so we did a little shortening of the limbs in the quadruped mode. We actually had controls that could scale the length of the two leg bones to make them look more appropriate. So we took a little more of a compromise approach to find something that was a good match to what was already shot and to try and work a little more in a truly dog-like fashion. Another issue was dealing with attaching the feet, which involved tracking and integration. The environment was very smoky and hard to see and hard for the tracking people to get information and it was hard for the composite people to get integration. Rather than being restrictive, we let them shoot what they want and dealt with it in post."