The studio also designed and produced an expansive CG medieval fortress environment which serves as one of the film's principal locations.
Luma has worked with Lakeshore in the past, most notably on last summer's The Cave, for which it served as the soul provider of CG intensive visual effects involving 3D creatures and environments. The studio also had an established relationship with the film's director, Len Wiseman, through the original Underworld film, on which is served as supporting VFX studio, completing nearly half the visual effects shots in that film.
For Underworld: Evolution, Luma was challenged with creating extremely sophisticated visual effects with high efficiency. The studio produced the effects in just eight months with a staff of 50 artists.
Luma's CG creature work appears in more than 100 shots. As characters regularly transform from human state to bestial form, Luma also had to produce digital doubles of the talent for use in creating the transitions.
The transformations could not be simple morphs. Rather, they had to occur organically. "The creatures' skeletal systems needed to change, stretching the muscles and tissue with it," explains Luma CG supervisor Vince Cirelli. "Skin needed to roll over bone mass, veins pop and blood spurt. One of the transitions happens so close to camera that you can see its pores."
Luma accomplished the transformations with a variety of off-the-shelf and proprietary tools. Artists used Pixologic's ZBrush to define skeletal transformations using just a few low-resolution base meshes. Luma's staff created their own plug-ins for character rigging, including a capsule deformer that allowed independent control over different aspects of the character transitions.
"The transformations had to look painful and sporadic," said Cirelli. "For this we devised underlying influence objects that pushed and pulled the skin. That was sequenced with a shader that output passes for compositors to make capillaries burst and skin bruise. We also employed stress maps to raise the creatures to photo-real level. Even with all this technology, the creatures would not look like they do without the incredible work of the modelers and texture artists here at Luma."
"For the fortress, we only had a sketch from the production designer outlining a general layout," adds Christopher Sage, Luma's texture and environment supervisor. "We gathered a large amount of reference materials from various public sources, but the director had something very specific in mind and the photos of existing castles that we found were less than ideal. We were able to take generic cues from the material we had compiled and the back-story of the film to develop a language to create this enormous and menacing castle."