The Advanced Art of Stop-Motion Animation: Visual Effects - Part 3
Rig and Shadow Removal
Making a puppet fly is a trick that has employed several different methods over the years. Often, the puppets would be flown on invisible strings, stuck to a plate of glass, or suspended by a rod holding them up from behind where the camera would not see it. These methods can still be used today, but in most cases, a rig is simply placed visibly into the frame to hold up the puppet and is digitally erased out of each frame of the animation afterward. This makes the animation process go much more quickly because you don’t have to worry about concealing any tools that are suspending the puppet. In post-production, it can become tedious and time-consuming, but this also depends on the length of the shot and how many frames need the rig removed.
One of the most straightforward ways to remove a rig from your stop-motion frames is simply to have a clean background plate prepared in addition to your animation frames. If you are shooting on any kind of set, shoot some frames of an empty set without the puppets in it and set those frames aside to use as a clean background plate in post. In the animation I did for the Thunderbean Stop-Motion Marvels! DVD, there were several frames of an empty stage at the beginning, and the entire scene was shot with a white limbo background. This made it pretty easy to select a background plate, and I would open this in Photoshop along with each of my animation frames (Figure 9.54). The next step is to paste the animation frame as a separate layer over the clean background plate (Figure 9.55). Then, with the animation layer selected, the eraser tool is used to simply erase the rig out of the frame, and the clean background plate will show through (Figure 9.56). It is best to make the brush size smaller and to use a hard edge for delicately erasing the rig at the edge of the puppet itself. Then, you can make the brush a bit larger for quicker removal of the rest of the rig. Once it is all erased, each frame is complete, with the puppet suspended in air (Figure 9.57), and they can be flattened to go back into the animation sequence.
Some of the trickier frames to work with on the Thunderbean project were those where the shadow of the rig needed to be removed but the shadow of the bean remained in the frame. Because the shadow was a little fuzzy, it was difficult to tell exactly where the edge of the bean’s shadow was. In the last few slow-in frames, it was also difficult to keep the shadow from jittering. To help soften the effect of the shadow’s edge, I used a feathered eraser tool instead of a hard-edged one and played around with the edge in the various frames until I got it to look right (Figure 9.58).