Making Waves in Animation

November 12, 2021

Making Waves in Animation

Epic Games has released Unreal Engine 4.26, delivering a range of new improvements including the production‑ready Hair and Fur that was recently featured in the Weta Digital Meerkat short film. It also delivers animation in the sequencer, sky and cloud environment lighting, better nDisplay support for Virtual Production (VP), a new water system, the remote control API often used in VP, and collaborative viewer template enhancements.

Hair and Fur

Hair and Fur are production-ready in 4.26, delivering the ability to edit, simulate, and render strand-based hair, fur, and feathers. Hair and Fur now features a new Asset Groom Editor for setting up properties and compatibility with features such as DOF and Fog. LOD generation is built-in, and users are now able to generate cards and meshes for lower-end hardware in-engine as an experimental feature.

Weta Digital recently completed a UE4 short film that road-tested the creative opportunities of using these new Unreal Hair and Fur tools in a traditional narrative story. The film was created with a small talented group of Weta Artists, but not using Weta’s proprietary hair tools, it was created with a pipeline of standard tools: Autodesk Maya, Peregrine Labs’ Yeti, and UE4’s 4.26 new Hair and Fur.

The team used Live Link to aid in their animation while in Autodesk Maya and then they exported an Alembic Hair Groom to UE4 for the final composition, lighting, and rendering. Live Link provides a common interface for streaming and consuming animation data from the external sources DCC software, such as Maya, into UE4. Thelvin Cabezas, CG supervisor at Weta Digital comments that “having the live link is part of what made this project possible… We adjust our animation controls in Maya and see what it looks like in UE4 and this gives us a really controlled approach to the way we work”.

The meerkat film was always designed to test using Unreal for making a traditional short film rather than an interactive game. The Unreal Engine’s Control Rig and Animation features in Sequencer were used to create the final piece, and then the Movie Render Queue was used for export. This provided a remarkable finished piece. The meerkat, named Molly, was groomed with 400,000 strands, the Eagle ended up with over 3.7M stands (even more than Weta Digital reported). In the past, artists might have had to address a bird’s wings using cards in a game engine, but the new Hair and Fur simulation produced feature film level, fully accurate winged feathers.

The Weta Digital piece not only showcases the new Hair and Fur, but it shows what talented artists can do, and how far these new easily accessible but cutting-edge tools have now come. The piece works not due to a special build or custom code that only the R&D team at Weta could write. It comes from the talented and experienced Weta animators using tools anyone can now get their hands on.

Adding further believability to their characters’ movements, users can now create animations in Sequencer by blending animation clips such as motion-captured data; the workflow will be familiar to animators who’ve worked in other nonlinear animation editors. Animators can preview skeleton animations to easily see how one skeleton blends into the next, and match joint placement for a smooth transition between clips. The feature is integrated with Control Rig, which now offers an experimental full-body IK solution in addition to the standard FK/IK.

Immersive natural worlds and environments

Unreal Engine 4.26 introduces a new Volumetric Cloud component that is able to interact with Sky Atmosphere, Sky Light, and up to two directional lights, improving the quality of both realistic and stylized skies, clouds, and other atmospheric effects. The atmosphere can receive volumetric shadows from meshes and clouds; lighting and shadowing updates in real-time to reflect time of-day changes. In addition, there’s a new Environment Lighting Mixer window that enables all components affecting atmosphere lighting to be authored in one place. This release alsosees the introduction of a new water system, enabling artists to define oceans, lakes, rivers, and islands using splines. Users can adjust and visualize the depth, width, and velocity of rivers along their lengths, and the wavelength, amplitude, direction, and steepness of waves on oceans and lakes. The system includes a new Water Mesh Actor that uses a quadtree grid to render detailed surfaces up close, smoothly transitioning to simplified ones at distance. Built -in fluid simulation enables characters, vehicles, and weapons to interact with the water; the fluid also responds to Terrain, such as reflecting ripples off the shore and reacting to river flow maps

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