Earlier this year, LAIKA was presented with a Science & Technology Academy Award for its Rapid Prototyping (RP) process, which saw its debut during the production of Coraline. LAIKA’s Director of Rapid Prototyping, Brian McLean, and Coraline facial animation designer, Martin Meunier, were cited: “LAIKA’s inventive use of rapid prototyping has enabled artistic leaps in character expressiveness, facial animation, motion blur and effects animation. Through highly specialized pipelines and techniques, 3D printing capabilities have been harnessed with color uniformity, mechanical repeatability, and the scale required to significantly enhance stop-motion animated feature films.”
The team at LAIKA effectively revolutionized the process in which character heads are replaced in order to create stop motion animation. Instead of swapping out the entire head, they created a multitude of upper and lower parts of faces which could be swapped out to create a variety of expressions and dialogue. The seam lines would then be removed and cleaned up in post, an entire process which is less time intensive than the previous way of animating.
Starting with Coraline, they decided to take replacement animation and apply it to 3D printing. On that film, the parts were printed out with a white resin and painted by hand. Over the course of the next three films, they continued to refine the process including moving to color printing (instead of hand painting) on ParaNorman and The Box Trolls. For Kubo and the Two Strings, releasing August 19th in the US, they’ve continued to push the technology even further.
There were an incredible number of facial parts printed during production. The Kubo character has 11,007 unique mouth expressions and 4,429 brow expressions, allowing for over 48 million possible facial expressions. Between the various Kubo puppets used on set, there were over 23,000 RP-printed faces.
For previous films, LAIKA utilized powder printers, where liquid glue is sprayed onto powder. It was possible to get good colors, but due to the use of powder it was difficult to get fine detail and sharp edges. “We had worked through that limitation on the past three films,” says Brian McLean, “but when we saw some of the character designs on Kubo and the Two Strings and we looked at particularly Monkey, Beetle, and this Moonbeast character, we realized the existing technology that we had been building over the last several years was not going to work.”
The hard edge features of the characters would prove problematic and they would have had to change the character design, such as softening out a lot of Monkey’s hair and softening the angles on Beetle’s face, or find a new way to execute the rapid prototyping.
Because of LAIKA’s groundbreaking work, they had actually developed quite a reputation not only in the animation industry, but also the 3D printing industry. “We had the clout to go to some of these 3D printing companies and say ‘hey…we have this project we’re working on and nothing is going to work for us. What do you have in development that might work for us?’”
They ended up using The Connex3 from Stratasys, a company LAIKA had been working with for years. The Connex3 is a multi-color and multi-material printer, allowing plastic color printing as opposed to the previous powder and glue solution. According to McLean, the hardware “is amazing. But the software that they had developed to run the hardware was not going to work for us.” So they got approval from Stratasys to develop their own software that would suit the needs of the rapid prototyping system. LAIKA worked with an outside programmer as well as in-house developers to create the software for their pipeline and create incredible results.
“If we were to take one of these parts to a 3D printing conference filled with 3D printing nerds from around the world,” says McLean, “they would swarm around this and say ‘how in the world are you guys able to do this? How are you able to get this level of detail out of plastic?’”
The main difference in quality is rooted in the technology. Powder 3D printing is based off of tech from 2D inkjet printing, where a final mixed color is jetted down onto a white substrate. Color mixing and things such as ICC profiles are all inherent in the solution based upon its heritage.
On the other hand, with plastic printing, colors can’t be mixed. Instead of color being jetted down onto a white substrate, plastic itself is colored — and as such, even white is being jetted down as another color. Since plastic can’t be mixed, multiple individual colors are jetted as tiny tiny droplets next to one another, effectively in a dithering pattern. When viewed at scale the tiny dots blend together to give the appearance of mixed colors. These dots are incredibly tiny — there are approximately 18 million droplets in a cubic centimeter.
A technological limitation the team had to overcome is the fact that the Connex3 printer is only able to print three colors at once. For instance, for Monkey the only colors used were cyan, white, and magenta. Another character might use only magenta, yellow, and black. Yet while limited, the technology also brings other benefits to table. This film was the first time the team at LAIKA was able to use translucency as a color because they are able to include clear plastic as an additional color. So by combining transparency with the colors and different resins, a wider variety of end result hues can be created. In addition, they used a variety of lights and light temperatures on-set to bring out or accentuate colors in the characters.
Another bit of the process the team pushed forward on for the film was scale, an example being a 200% scale Kubo head that was used in production. This was required for key extreme closeup of a tear on Kubo’s face at a critical story junction. The team was concerned that a normal scale head might show off too many of the imperfections and difference between the individual face replacement parts.
“It’s one thing to zoom into an object and make one face look good,” says McLean, but when replacing a different face part every frame “any inconsistency with the geometry, or color, or even the surface texture would translate into some chatter and noise.” The knew at 100% scale it wasn’t going to hold up so they went with a scale that would be much more forgiving, which was a face about 4 1/2 inches across. As a side note, the smallest replacement face on the film was a Monkey face used when Skeleton had her in it’s clutches. That face measured just half an inch across.