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New real-time demo, Lion: Unity Art Tools in action and the future of Wētā Digital for RT3D

August 10, 2022 in Technology | 15 min. read
A lion cub playing with its parent in the savannah
A lion cub playing with its parent in the savannah

Lion brings artist tools from Wētā Digital, Ziva, SpeedTree, SyncSketch, and the Unity Editor together for the first time.

Lion marks a key milestone for our Unity Art Tools, and illustrates our ongoing work to build tools that empower creators.

This collaborative demo showcases what happens when artists and developers work together at the production level to push the boundaries of what’s possible for real-time, high-fidelity visuals.

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This combined production and technological effort features innovations in real-time technology that shows content created with Wētā Digital, SpeedTree, Ziva, SyncSketch, and the Unity Editor artist tools – now part of an integrated demo in a real-time pipeline, experienced on consumer hardware, running at 30 fps at 4K on PlayStation 5®.

The original offline demo assets were created by students from the Monster Emporium Animation School, with lions simulated in real-world measurements using the biomechanical elastic-body solver in Ziva VFX for soft body dynamic simulation.

Two grey lion cubs in Unity Editor side by side, walking and stretching
Example simulation in Ziva VFX for the cub sitting down sequence

The scene was then updated to enable a highly performant real-time experience. The lion assets were enhanced with machine-learned Ziva RT deformations, executed dynamically using the new Ziva RT Unity player (launching in Preview at SIGGRAPH 2022), which provides the utmost fidelity deformation.

A lion cub walking in the Unity Editor, with no colours
Ziva RT gives animators final-quality deformations while also accelerating the evaluation speed of their rigs in the authoring tools for a faster DCC iteration workflow. In this example, Ziva RT was trained using the new quasi-static integrator in Ziva VFX 2.0, which provided both accurate and robust results, ideal for the purpose of training real-time deformations.
Two grey lion cubs in Unity Editor side by side, walking and stretching
Compare the high-fidelity deformation with Ziva RT and a more traditional skinning animation typically used in games: The differences of musculature and soft tissue are particularly noticeable on the silhouettes and under the shoulder blades of the cub.

For optimal performance at runtime, Ziva RT Unity Player executes SIMD-optimized code in a parallel manner, leveraging Unity’s Burst technology for the dynamic interactive deformations in real-time. 

The new demo environment also features vegetation from SpeedTree. We started from assets created with SpeedTree Cinema, and optimized them for real-time to add some dusty tufts of grass near the lions and build the iconic shape of an African mopane in the horizon. These exports are Games FBX with individual high-resolution textures that allow the plant assets to match resolution to the finely groomed creatures.

A sketch of a lion looking into the distance in a savannah
Adding just a small bit of vegetation helps frame the composition and liven up the environment.
A patch of grass with two SpeedTree trees on each side of it
Example of SpeedTree assets

To achieve realism, Wētā Digital’s hair and fur groom tool, Wig (pre-alpha), complemented Ziva’s deformation technology by adding another layer of fidelity and artist directability to create the big cat’s mane and fur grooms on both the lion and cub.

“Wig is a different way of working – it’s actually the fastest grooming tool that I’ve ever used,” says Sara Hansen, a Unity technical artist on Lion who has previously created production grooms for Wētā FX, DNEG, and other VFX houses. 

“A high-quality hero groom – which would take me several months in another grooming package – is much faster to create in Wig. It takes just a couple of weeks, and some grooms go from weeks to create in other tools, to only one or few days in Wig, and at far better quality levels and with greater artist controllability… Even when you have to react to detailed art direction feedback notes, like adjusting a specific strand from a reference shot, it’s easy to author in Wig.”

A lion's mane being created in Unity
Example of authoring the lion’s mane using Wig

The team behind Lion was distributed across multiple countries in North America and Western Europe. Their remote teamwork was made possible by visual collaboration tool SyncSketch, which provides the ability for real-time production reviews and intuitive iteration.

A model lion on the left, with a real picture of a lion on the right
Example of the lion’s in-progress groom review in the cloud-based SyncSketch collaboration tool

Production validation of Wētā Digital’s Wig, Ziva, SpeedTree, SyncSketch, and the Unity Editor through this creative exercise allowed the team to iterate quickly and improve the workflow for end-to-end creatures and characters – creating connections from rigging to deformations to hair and fur attachment systems, rendering to shading, and more, into a coherent system.

“We want to ensure that our tools work together and enable creators to have great workflows for authoring characters and creatures end-to-end. So, part of the goal behind creating this demo was to help validate our Unity Art Tools in a production setting, solving real production needs that artists face on a regular basis and making our tools and workflows better and more robust throughout,” says Natalya Tatarchuk, Distinguished Technical Fellow and Chief Architect, VP, Professional Artistry and Graphics Innovation at Unity Technologies.

To accomplish realistic and believable creature and scene rendering that runs in real-time on PlayStation 5®, Xbox Series X|S®, and PC, a number of key technology innovations were developed.

The project began with Unity’s High Definition Render Pipeline (HDRP). We used Global Illumination (GI), which was achieved by leveraging Adaptive Probe Volumes (APV) to light the arid desert and vegetation surrounding the lions.

A lion shakes its head while a cub plays with its mane

The team had to tackle the challenge of simulating and rendering several million hairs on high-fidelity grooms. In order to achieve this, a significant set of performance and visual-fidelity improvements were made to HDRP.

One set of improvements includes a new GPU-driven clustered hair simulation that enables millions of hair strands to react dynamically in real-time, part of the new Hair System released on Unity’s GitHub. This builds on the hair simulation used for the incredible Digital Human showcase, Enemies, and expands the method to handle several orders of magnitude more hair strands efficiently on GPU.

For hair and fur rendering, the graphics developers at Unity designed a set of improvements to a GPU tile-based software rasterization algorithm in HDRP, with significant optimization to render several million unique hair strands. This method achieved smooth visuals with analytic anti-aliasing with compute-sorted order independent transparency for hair strands, and improved advanced physically-based hair lighting models for film-quality hair strand rendering. 

This approach means that we can now render millions of individual hair strands, all moving independently and uniquely, without artifacts. It accurately preserves the hair highlights and the way that the light shines through soft hair, such as on the cub’s fur or the lion’s mane in the sunlight.

These hair simulation and rendering improvements, hardened by this and other productions, will be landing in the 2023.1 Tech Stream.

A lion cub tussling and playing with its parent

Many of our tools are already available and are used in productions throughout the world, and we can’t wait to share more with creators everywhere.

SIGGRAPH 2022

Lion will demo at SIGGRAPH 2022 during this session at the Vancouver Convention Centre:

Lion: A glimpse of the future with Unity Art Tools
Speakers: James Jacobs (Unity Technologies), Anton Blake (Monster Emporium), Julio Cesar (Monster Emporium), Sara Hansen (Unity Technologies)
Wednesday, August 10, 2:15–3:15 pm
West Building, Ballroom C/D

Join us to watch the premiere of Unity’s latest demo, Lion. This production features innovations in real-time technology through content created with Ziva, Wētā Digital, SyncSketch, SpeedTree, and the Unity Editor artist tools. Lion showcases plans to help artists create visuals that push boundaries, as well as foundations for richer creator workflows.

Further talks on the technology and artist tools involved in this showcase:

Intro to Ziva Face Trainer: Auto-rigging real-time 3D faces
Speakers: James Jacobs (Unity Technologies), Crawford Doran (Unity Technologies)
(available online following SIGGRAPH 2022)

Creating organic environments in Unity 2021 LTS
Speaker: Xiaoxi Liu (Unity Technologies)
(available online following SIGGRAPH 2022)

Artist-friendly features in HDRP
Speakers: Sean Puller (Unity Technologies), Alix Mitchell (Unity Technologies)
(available online following SIGGRAPH 2022)

Ziva for feature animation: Simulation and machine learning-ready workflow
Speakers: Brian Anderson (Unity Technologies)
Wednesday August 10, 9 am–12 pm
West Building, Room 116-117

SpeedTree Cinema: From concept art to VFX asset
Speaker: Sarah Scruggs (Unity Technologies)
Wednesday August 10, 10:30–11:30 am
West Building, Room 116-117

Advances in real-time rendering in games: Part III
Speakers: Natalya Tatarchuk, Francesco Cifariello Ciardi, Lasse Jon Fuglsang Pedersen, John Parsaie, et al.
Thursday, August 11, 2:15–5:15 pm
West Building, Ballroom C/D

Topics covered will include probe-based lighting, the strand-based hair system, and physical hair shading model.

Introduction to Ziva RT: Bringing creature sims into Unity with Monster Emporium and Ziva RT
Speakers: James Jacobs (Unity Technologies), Anton Blake (Monster Emporium), Julio Cesar (Monster Emporium)
Thursday, August 11, 2:15–5:15 pm
West Building, Room 116-117

Visit our site for more information and a complete list of Unity sessions at SIGGRAPH 2022.

August 10, 2022 in Technology | 15 min. read
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