KEY CONCEPT: Less-than-stellar stylized character design can be brought to life by well-posed facial expressions. Case in point, the two different facial designs of “Sonic the Hedgehog" developed for the recently-released movie.
The first "Sonic the Hedgehog" movie character design (Sonic #1) incited a fan revolt, but certain facial details were singled out for blame like the realistic teeth and the small eyes, But, as I explain below, the character's underwhelming facial expressions were the fault of poor posing and a too-narrow jaw.
The “Sonic the Hedgehog” movie had an unusually bumpy road to its release. When the original trailer appeared in 2019, there was intense on-line protest from fans who unfavorably compared Sonic #1 to the older video game Sonic character, objecting strenuously to various elements of his design. Very unusually, the studio quickly announced that they were delaying the movie's release by three months so they could do a serious make-over. The newest movie, featuring Sonic #2, was greeted with universal approval when finally released.
Figure 2. Here are the two Sonic movie character designs side-by-side. Sonic #2 is closer to the video game original with much larger eyes, smoother texture and vertically-stretched irises. Also, his face is more expressively posed - note the distress brow and wider open mouth.
Complaints about Sonic #1 included all manner of details, like his body shape, proportions, lack of gloves, and head size. When it came to his face, many fans objected to Sonic’s very realistic teeth, finding them too human, to the point of being creepy. Others said that his face in general was so realistic that it fell on the wrong side of the Uncanny Valley. The eyes were also faulted for being too small.
None of these factors were the actual source of the problem, from an expressive point of view. Sonic #1 is so distant from a real person on the "human-to-cartoon continuum" that such discomfort is not an issue.
Figure 3. The Polar Express (2004) is often cited as a worse case scenario for its proximity to the Uncanny Valley, with one critic calling it “a failed and lifeless experiment”. Later movies have either kept things more stylized (Avatar), or used animators to correct for the details that simple motion capture did not get right (like Thanos in the Avengers films).
From the point of view of facial expression, there were two key problems with Sonic #1. First, careless, or uninformed animation of his facial expressions and second, a jaw that is too narrow to emote Joy and Fear which depend on a wide mouth.
Take the Fear face, for example. When the face is properly configured with widened, obliquely-occluded eyes, and an opened, stretched mouth, neither the size of the eyes nor the realistic teeth are an issue. The Sonic #1 pose in Figure 5 lacks any widening of the eyes (they are in their default position) or modification of the crucial Upper Eyelid Interface (UEI). In order to widen the mouth sufficiently, I had to add more width to the jaw region, as the original character design was too narrow to allow for enough sideways stretch.
Figure 4. It’s never the size of the eyes that matters, but their shape. Here I have greatly improved the Fear pose of Sonic #1 by opening his eyes and adding the distress brow which was missing from the original. I’ve also re-posed the mouth, dropping it more open, and stretching it sideways. Note that the sideways stretch required rebuilding the lower face to allow more room, something the character designers accounted for in Sonic #2. And for those who complained about the too-realistic teeth, they are a non-factor, having no effect on the final expression.
Sonic’s original smile was also kneecapped by the narrowness of his jaw. Based on what we saw in the trailer, his smile was seriously underwhelming – making a smile wide enough is a crucial part of its effectiveness. My corrected version (Figure 6 - right) includes a widened lower face, as well as the eyes being occluded by the lower eyelid, a feature of the true smile (though one often ignored by animators).
Figure 5. One thing animators should get right is the smile. However, Sonic #1' s smile is both the wrong shape and too cramped by the character design. In my modified version, by widening the lower face, I was able to stretch the mouth considerably and tilt the outer corners of the mouth. I also cropped the iris from below with the lower lid - stylized smiles don’t require this detail, but it is a crucial part of the actual human smile.
To give credit where credit is due, Sonic #1 did get anger right, making the missteps in some of the other expressions all the more mysterious. Sonic #2 seen here alongside Sonic #1 is equivalent in the degree of rage, and the animators used the UEI to good effect.
Figure 6. One thing the Sonic #1 animators got right is the expression of anger. Here the UEI is correctly posed, interacting with the widened eye to create a very effective angry glare. The equivalent pose in Sonic #2 matches, but does not surpass, the original character design.
The many adjustments to Sonic #1's facial design that had nothing to do with expression – including the simplified, much more stylized nose, the suppression of the fur texture in favor of a more plastic look – were combined with a more mobile UEI, radically increased eye size and a widened lower face, to allow the CG artists to animate a more expressive, appealing face.
That said, Sonic #1, as I demonstrate, had the potential to be more expressive, if the character designers had widened the jaw. But given the fan's overwhelming desire to have the movie character Sonic match the video character Sonic, it's clear why the studio decided on a major redesign, as opposed to a tweak. Would Sonic #1 have worked if there wasn't a video version to compare him to? We'll never know - but now we know how to improve his expressions of Joy and Fear.
BTW, this is what a real hedgehog actually looks like!
CREDITS : Figure 1. Images of Sonic from the Japanese video game series and media franchise created by Sonic Team and owned by Sega; Figure 2, 4, 5, 6 & 7. Images of "Sonic the Hedgehog" movie characters (designs #1 & #2) from the action-adventure-comedy film based on the video game franchise published by Sega. Originally Sony Pictures collaborated with Sega Sammy's Japanese studio Marza Animation Planet, then Paramount Pictures acquired the movie rights in 2017. It was released on Valentine’s Day 2020.; Figure 3.. Image of the unnamed boy from "Polar Express" movie (2004), the first all-digital capture film based on the 1985 children's book of the same name by Chris Van Allsburg, Co-written, co-produced and directed by Robert Zemeckis, and produced by Castle Rock Entertainment in association with Shangri-La Entertainment, ImageMovers, Playtone and Golden Mean Productions for Warner Bros. Pictures. The visual effects and performance capture were done at Sony Pictures Imageworks.