Unreal Engine 5.4: A Game-Changer (LITERALLY) for Developers
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Unreal Engine 5.4 prioritizes performance enhancements. Users can expect significantly faster Lumen, shadows, and ray tracing. Variable rate shading for Nanite has been implemented, and instance culling and renderer parallelism have seen major improvements. These optimizations translate to real-world benefits, with city sample demos showcasing a 50% reduction in render thread time and a 25% decrease in GPU time.

One of the most significant additions is production-ready motion matching. This powerful tool eliminates the need for handcrafted state machines. Instead, it dynamically selects the most fitting animation frame from a database, closely matching the character's current pose, past movements, and future trajectory. This not only simplifies animation workflows but also leads to highly believable character behavior. Motion matching extends beyond locomotion, enabling seamless transitions for jumping, falling, and complex traversal. Additionally, 3D trajectory prediction ensures smooth transitions with anticipation and follow-throughs. The system boasts robust monitoring and debugging tools, including a rewind debugger for analyzing and refining transitions within the motion database. Notably, motion matching has been battle-tested in Fortnite Chapter 5, running flawlessly across all characters and platforms. To empower developers, a free sample project will be released, featuring over 500 high-fidelity animations and a local motion and traversal dataset used in the demo. This project is compatible with the MetaHuman rig, further streamlining the animation process.

Unreal Engine prioritizes empowering storytellers. Control Rig and Sequencer animation authoring tools have reached a significant milestone, with the entirety of Lego Fortnite's animation being produced within Unreal Engine, eliminating the need for external DCC software. This streamlines the workflow by enabling real-time iteration on animation, camera angles, and lighting within the engine itself. Additionally, the new suite of deformers in Control Rig empowers the creation of complex rigs with features like squash and stretch, offering animators more creative freedom.

Understanding the importance of developer experience, Unreal Engine 5.4 boasts significant improvements in C++ compilation times. The new Unreal Build Accelerator facilitates highly performant distributed code builds, leading to unrelated third-party compiles being two to three times faster. Additionally, fewer shaders are compiled within the editor and during cooks. Lastly, onboarding for large distributed teams has been enhanced through the Unreal Cloud DDC.

MetaSounds, the foundation for audio in new Unreal Engine experiences, has received further attention. From granular vehicle synthesis in Rocket Racing to sample-accurate weaponry in battle royales, MetaSounds empowers sound designers to craft truly immersive and unique soundscapes. A new experimental audio profiling tool called Audio Insights is also being introduced, aiding sound designers in creating impactful audio experiences.

The PCG framework, initially introduced as experimental in the previous version, has received a substantial upgrade. Artists can now leverage runtime hierarchical generation, attribute tables, and feedback loops to create vast, art-directable worlds with a high degree of efficiency and determinism. Notably, the PCG framework played a pivotal role in Lego Fortnite's world creation. The team developed a system that generates unique tiles assembled on the fly, resulting in a unique world for each player. These learnings translate into new possibilities for developers to utilize the framework, build custom tools, and create innovative gameplay experiences. To empower users, a PCG biome creation plugin will be released, showcasing a data-driven tool built with the latest framework improvements. Importantly, the PCG framework is on track to be fully production-ready by GDC 2025.

Lego Fortnite served as a real-world testing ground for several new features. Chaos physics received significant optimizations to handle large-scale building and destruction. A new prediction model minimizes physics object corrections, ensuring a smooth experience. Notably, the multiplayer physics sandbox operates server-side, guaranteeing consistent and performant simulations across platforms. Unreal Engine's data-oriented programming framework, Mass, was pushed to its limits, successfully simulating and managing over 6 million lightweight actors. Lastly, engine storage and memory usage optimizations ensure Lego Fortnite runs impeccably across all platforms, including mobile devices.