Spin VFX Makes a Splash with Water, Light & Creature FX for ‘Dolphin Tale 2’

In the original film, ‘Dolphin Tale’, a young boy finds and untangles a dolphin caught in a crab trap. Badly injured, the dolphin is taken to Clearwater Hospital. Her tale must be amputated, but she receives and learns to swim with a prosthetic tale. In this second film, ‘Dolphin Tale 2’, the hospital needs to find a companion for the dolphin so she can continue to live at the aquarium.

The dolphin characters of this story are real dolphins actually living at Clearwater Marine Hospital, a active working aquarium. Although the production VFX supervisor Bob Munroe was carrying on in his role from the first movie, Spin VFX based in Toronto, Canada, only entered the production at this point. Spin’s VFX supervisor Colin Davies joined him on location in Florida at Clearwater Marine Hospital for part of the on set supervision work prior to the start of principal photography.

At the Aquarium

Bob explained that while dolphins are intelligent and friendly, it’s difficult to persuade individuals to cooperate in a linear, story-like scenario, and visual effects helps work around this fact. “When the ‘stars’ got tired or restless we could use available, enthusiastic dolphins to stand in for them and then adjust their attributes in post,” he said.

In the course of supporting the story, Spin needed to create full 3D dolphins as well as augment the live dolphins, and this meant animating controlled CG dolphin performances and integrating them into live action plates and CG water environments, above and below the surface. CG surface water simulations, water interaction with live and CG dolphins, surface disturbance and undulation, splashes, underwater churn, reflections, refraction and the look of wet skin were also added to make their work invisible and photoreal. By the end, they delivered over 220 shots.

Bob put a lot of effort into surveying every aspect of the hospital areas used as the set and the dolphins themselves, taking complete, precise measurements. An animatronic dolphin was built to scale to use as a reference object in the images, and exhaustive texture shoots were done for the dolphins’ skin. The interiors of the tanks were measured and all details of the tanks photographed. For the animators’ reference, the aquarium’s in-house videographer shared his huge library of footage of the same dolphins that were appearing in the movie, and Bob shot further video of them as well.

Perfect Skin

For part of this pre-production research, Colin Davies also visited the set and worked in the pool directly with the dolphins. “In several shots, our CG dolphins were in frame with real dolphins. There was no where to hide. We had to get the performance, the look and the integration just right or the shot wouldn’t work,” he said. “It was important to understand how dolphin skin behaves and responds to water. Instead of letting the water bead up, it had a fine micro-pore surface that retains water like a sponge and. At the same time, the wet skin serves as a sun block. The way it affects the water dispersion produces very distinctive light effects that I had to see myself to understand.”

Armed with all of this set information and reference, plus the typical lens data and HDRIs, the Spin VFX team at the studio could build and light extremely accurate environments in which to test all of their looks and assets. Carrying out all of the renders within those environments helped them produce physically plausible results from their shaders, which was critical for realism.

Furthermore, having the video reference of the specific dolphins in the movie was invaluable to Spin’s animators, led by animation supervisorPeter Giliberti, who modelled, rigged and animated the creature characters in Autodesk Maya. Bob and the rest of the creative team that had worked on the first film had gained a lot of expertise in dolphins’ behaviour, their moves and the way they accelerate through the water, and their experience also helped Peter’s team.

Dolphin Manoeuvres

“Actually, not very much movement shows externally, so you have to study their underwater mechanics, avoid over-animating and strike a balance to get just the right flick of the tale. An animator sometimes tries to anthropomorphise a creature for the sake of the story but, while these dolphins do have distinctive personalities, we had to make sure the animation was absolutely real,” Colin said. “Less can be more sometimes, and imply a thinking process. As dolphins are creatures we didn’t have any associated facial movement to help with story points, either.”

Everyone noticed that dolphins are extremely curious, especially the younger ones, and alertly watch every move around them. As Bob and his team surveyed the pool, the cast were fascinated by their activity with tape measures and other equipment.

Spin VFX has a lot of experience working with water after completing several different project with water as a key element. On this movie, the proximity of the camera introduced an extra challenge. During look development, they wanted to carry out their water simulations, created in Houdini and rendered in Mantra, at a high enough resolution to give them a useful preview of the result, but still have the time to run through enough iterations to get the look they wanted.

Faster Lighting Pipeline

Then, once they were satisfied with the simulation, they had the complication of raising the result to full resolution, which stretched their software to the limit of its cache size. Some of the water simulations were huge and took days to render. Colin said, “Our effects supervisor Tim Sibley was very good choosing the right resolution to work in at any point in the process, which was important to prevent us getting behind. If your test resolutions aren’t high enough it’s easy to judge incorrectly about how a simulation will look in the final render.”

To handle the many light interactions accurately, lookdev and lighting supervisorDoug Addywith Spin’s lighting team used KATANA, connecting to their renderer, RenderMan. “On this project we were taking advantage of KATANA as a pipeline tool, making scene assemblies and scene updates much quicker, and making changes to backgrounds and animation fairly easy. Once we know the lighting is working correctly in a particular shot, we can template this and brig it into other shots,” said Colin.

“We were also using RenderMan’s new ray tracing and physically plausible shaders, which contributed further to the realism. Having those, plus all of the set and light reference helped us stay in the scene’s linear workflow, that is, where the specific light energies we were using precisely matched the light energies of the sun on the day of the shoot. All of these techniques improve your ability to re-create and accurately render light interactions.”

Water, Colour & Light

The project’s colour workflow was interesting for several reasons. One was the need to photograph and re-create scenes above and below the surface of the water, another was the use of more than one camera type and another was working with DPDaryn Okada, who wanted to use a linear colour pipeline. 

Most of ‘Dolphin Tale 2’, above and below water, was shot onSony F55andF65cameras. Daryn was keen for Spin’s team to have the F65’s 8K resolution for the effects work, which they re-sampled down to 2K for delivery. However, during the first week of the shoot, the production lacked underwater housing for the F65, and used anALEXAfor underwater shots instead. Colin said, “It was the first time we had worked with Sony’s Cine Alta cameras and its colourspace, and the need to work on shots from both Sony and the ALEXA was a fair test of our colour pipeline.”

Daryn used an LUT from Technicolor that allowed them to work with linear EXR files natively. Daryn did quite a bit of grading on set, and Spin VFX could use the same colour set-up to view their renders in NUKE, showing them how Daryn envisioned the images. “This isn’t so unusual nowadays, but it is an example of a film taking a step closer to an ACES type of colour pipeline - not exactly, but a close approximation,” said Colin. “It also meant we could work with images that were beautifully shot as well as graded by the DP, retaining all colour depth and dynamic range.

“It became a challenge for us on the underwater shots. These were graded especially heavily because water naturally filters out red light, and the footage without the LUT looks very flat. Daryn graded much of the red and magenta back in, so those colours really pop. It looked great but presented us with the challenge of setting up our assets and renders in a way that would produce the intended result. DPs are starting to think a lot more about what will happen in post production, which takes getting used to on both sides.”  www.spinvfx.com

Words: Adriene Hurst
Images: Courtesy of Warner Bros Entertainment