During the battle between Thor and Destroyer, Thor spins his hammer at incredible speeds, creating a super tornado that lifts CG cars, debris and Destroyer into the air. Luma's in-house software programming staff designed tools for the vfx team use to help visualize the large amounts of data needed for the supercell generation. This allowed them to design the lighting and shot composition before rendering dense data sets.
For Destroyer's blast, Luma used a mixture of high velocity fluid simulations and dense particle renders driven by geometry.
For traveling the cosmos from Asgard, they used a rainbow bridge called Bifrost. This is a solid, crystalline bridge that leads from King Odin's palace in the center of Asgard out to the edge of a saturnal ocean, where it connects up with the ancient Heimdall Observatory. "The crystalline rainbow bridge and all the visual effects around Heimdall's Observatory were done by Buf, supervised by Nicholas Chavalier with supervising vfx art direction by Pierre Buffin," Sewell adds. "This is a beam moving so fast that it stretches the spectrum of light into what could be perceived as a rainbow. Buf did many of these blasts into space [Luma created others using voxel rendering techniques and complex lighting rigs inside funnels], including our stunning end title sequence, where we travel from Earth through a wormhole, past a black hole event horizon, on through a fractal increase in scale, until we behold the entire universe as a magnificent tree, a literal Yggdrasil. Then we zoom through its trunk and branches until we reach the top and find Asgard. Here we attempted to create a cinematic first where we ride from one destination to another across the cosmos with an exciting sense of scale, grandeur and breathtaking beauty."
Meanwhile, the stereoscopic 3-D conversion was performed by Stereo-D (Graham Clark was the stereographer), which mainly worked with actual geometries rather than volumetric illusions, while DD provided 80 some CG shots in full native stereo. "If you have proper geometries and project the original film image on it, you can 're-photograph' it with two virtual cameras in the computer," Sewell continues. "This is how it resembles true stereo photography. There is a bit of tearing and stretching that occurs in each 'eye,' but this is easily cleaned up with our typical visual effects paint tools. One of the other things that I liked about Stereo-D was that they were visual effects friendly. This is important because stereo conversion is essentially a visual effect using similar techniques and technology we use for the effects in the film. We should not only be compatible but also collaborative. Stereo-D embraced the opportunity and were excited by the possibility of this interchange."
Buf handled crystalline rainbow bridge and everything around Heimdall's Observatory.
Bill Desowitz is senior editor of AWN & VFXWorld.