The Advanced Art of Stop-Motion Animation: Visual Effects - Part 2
Advanced Compositing for Ava
In Chapter 4: Digital Cinematography, I included some information that was shared with me about a moving camera shot from Lucas Wareing’s student film Ava, made at Emily Carr University of Art + Design. The camera move itself starts by pointing up at the ceiling of the film set, and then begins tilting down and moving forward through the set. The camera moves through a bunch of real foliage and eventually ends in front of the monster, Charlie, who is sleeping between two cliff facades built as part of the stop-motion set. Meanwhile, there is the effect of a moving sun being animated behind to create a real lighting change throughout the whole set. The background behind the set was a plain white backdrop, instead of a green or blue screen. This was done deliberately to better match the lighting throughout the scene and to avoid worrying about blue or green reflections spilling into the set. The original footage from this particular shot in the film (Figure 9.43) went through a complex process of compositing afterward in post-production. The visual effects for this shot would involve a digitally created matte painting of a night sky from which the camera would tilt down, eventually revealing a sunrise in the far background behind the stop-motion set, including an animated sun that followed the path of the lighting change created physically on set (Figure 9.44). Lucas and his compositor, Henrique Moser, shared with me some of the steps involved to complete this shot.
The first step was to use a steadiness plug-in to minimize some of the camera shakes that resulted from the physical stop-motion camera move. Next, the camera move was tracked to create a virtual 3D version of the movement of the camera on the physical set. This was done using PFTrack, a software program used for match-moving 3D elements to live-action plates with exact precision. The shot starts with the camera’s position extended past the beginning of the stop-motion camera move, pointing up at the matte painting. The virtual camera tilts downward across the sky portion of the painting, and eventually merges with the tracked version of the physical camera moving through the set.