1. Take the illusion literally
Optical illusions are ambiguous images that can be interpreted in more than one way. The trick involves making elements in the drawing look quite vague, which leaves a lot to the viewer’s imagination. But to animate an illusion, you’ll need to take the elements of the drawing that are only implied and figure out what they’d look like if we could see them properly. Here I had to imagine if the figure literally had the two faces, and I drew what I imagined the old and young woman would look like if they were facing us.
2. Explore dimensionality
Optical illusions function because of the limitations of drawing; this is because a flat image with simple mark-making can be interpreted in multiple ways. This is especially true when it is rotated upside down. When animating the illusion, I explored how ambiguous lines in the piece can be interpreted as either flat or dimensional. I did this by animating the same drawing in two different ways, revealing different dimensionalities with these tricksy lines. So, a forehead wrinkle becomes a nose, and hair can become a beard.
3. Dramatise geometry with characters
There are some amazing geometric tricks, such as the Penrose staircase, which seems to go endlessly up, even though it’s a small visual loop. A great way to highlight how mind-blowing this illusion is, is to have characters interacting with this ambiguous geometry. Taking a cue from M.C.Escher, I went back to the original Penrose staircase design and animated my own characters endlessly walking up it. As you can see, this took some careful planning to plot their footsteps.
4. Forget about perspective
3D space is the enemy of a geometric optical illusion; this is even true when the space is represented in two dimensions using perspective. The is because perspective is such an effective technique for depicting 3D space that it removes much of the ambiguity that could fool the eye and create an optical illusion.
Thank goodness for isometric drawing, a technical drawing approach that evens out the foreshortening of the image and means that the height and distance of an object become ambiguous. This leads to a confusing intersection of lines which forms a wonderful basis for an optical illusion like this staircase.
Here characters walking in opposite directions all appear to be going up the stairs. It’s interesting to follow the shape of one of these deceptive steps and see how its lines simultaneously describe different parts of the geometry of the staircase on either side of the drawing.
5. Teach an old illusion new tricks
In animating an optical illusion, we’re combining the tricks of the page with the bag of tricks that make up animation. This morphing illusion was originally a series of drawings that morphed from a head into a full figure. By passing your eyes over the original sequence, the viewers can almost animate it in their minds. I was happy to take this to its logical conclusion by hand animating it. In the process, I was able to use animation techniques unavailable to the original artist and polish up and simplify the animated morph. This smoother animation drew the viewer’s attention back to all the ingenuity of the original illusion.
6. Combine illusions in a sequence
Optical illusions are like magic tricks waiting on the page. As you look at them, you step into their isolated and idiosyncratic worlds. When I had finished animating each one separately, I realised that they all had one thing in common: a character. Using the animation trick of morphing, I could transition between the characters and use this as a linking device between the illusions. When they were all combined into one seamless animated sequence, I was happy not only to have connected these different illusions with the art of animation but to have connected them with each other.