Shared Connections
2D tracking is a process which analyzes video in order to follow (track) objects on screen. The process can be used to hide, remove, or even add objects to a shot that were not originally in the composition. The objects appear to be locked to the environment while the camera moves. Shared Connections was the perfect project to flex our tracking muscles because it called for animated elements to be added to a live-action character moving within a shot that was hand held. The Shared Connections project involved developing a look for the spiderweb of social connections and a work flow to create those dynamic animations. The animations then needed to be tracked onto our main character. Assets were compiled that would become our panels, acting as anchors for all of the drawn connections. There were basically two animations for every panel. Each panel had an expression to make it float in 3D space. The other expression controlled the animated lines so that where ever the panels were, the lines would always draw towards and lock onto them.
Panels were animated to float in 3D space.
Next, the animation had to be tracked onto our main character. Both, point trackers and planar trackers were tested before the final track was applied. A point tracker does just that, it tracks a point. It picks a pixel and tracks nearby pixels in order to gauge what movement is occurring. These types of trackers have their pro’s but the biggest limitation is that they are not very good at taking in the big picture. This is where planar trackers come in. The best thing about planar trackers is that they really do look at the image data as more of a whole. They work by assigning a 2D plane to an object in the scene. The computer then matches the two and tracks the video so that when one twists or grows the other will do the same. So in the case of Shared Connections whole body parts could be tracked instead of tracking a shadow here and there.
Masks were created to make the connections appear to be behind her.
Initially the animations were tracked to the character’s head but it put a large emphasis on any head movements that occurred. The twisting and bobbing of her head would make all of the panels shift around the screen to the point where they were more of a distraction than anything else. Ultimately, the solution was to track everything to her torso. This gave the effect that all of the panels were following her, almost as if they were connected to a backpack. In order to help sell the trick, lighting was added to the panels. The light was animated to look as if sunlight was coming through the trees and hitting all of those panels as she walked down the trail. The lighting effects and rotation of the panels in 3D space, coupled with the tracking, sell the idea that those panels really are floating around next to her.