This week, a new tech demo for new and upcoming Unreal Engine 5 features was shared under the guise of The Witcher 4. CD Projekt Red made it clear in a statement to VGC that what was shown "is a tech demo, and a first look at the cutting-edge technology powering The Witcher 4 - but not The Witcher 4 itself."
With that in mind, CD Projekt Red and Epic Games showed off this tech demo as part of Unreal Fest 2025. The demo takes place in the region of Kovir, a location that may or may not actually appear in The Witcher 4 itself. The demo shows Ciri in the "midst of a monster contract" along with "some of the innovative UE5 technology and features that will power the game's open world."
The presentation followed main protagonist Ciri — along with her horse Kelpie — as she made her way through the rugged mountains and dense forests of Kovir to the bustling port town of Valdrest. Along the way, CD PROJEKT RED and Epic Games dove deep into how each feature is helping drive performance, visual fidelity, and shape The Witcher 4’s immersive open world.
You can watch the nearly two-hour long presentation here. Alternatively, you can scope out just the relevant bits with The Witcher 4 below. Again, this is just a tech demo for Unreal Engine 5 features. There is a good chance that none of what you see here will actually make it into The Witcher 4.
Unreal Engine 5 Tech Rundown
UNREAL ANIMATION FRAMEWORK (UAF) powers advanced blending, state machines, and procedural animation workflows, ideal for scenes with many complex characters in motion, like Valdrest Market. The result? Smoother coordination, smarter runtime efficiency, and scalable performance.
FASTGEO STREAMING is a streaming system developed by CD PROJEKT RED and Epic used throughout the demo. It's optimized for quickly loading static geometry so it doesn't affect gameplay, using a lightweight method to register and unregister assets in graphics and physics scenes. You can see it best when we catch up to Ciri through the sweeping forest. There's no object pop-in or visual hiccups, just smooth, seamless world loading without compromising World Partition features like Runtime Data Layers or HLODs (The Hierarchical Level of Detail).
NANITE FOLIAGE uses Nanite's virtualized geometry system to render dense, detailed environments, like the forests around Valdrest, without compromising performance. It dynamically renders only the visible details at runtime, making it possible to populate vast landscapes with complex assets like trees and plants, efficiently and realistically.
MASS SYSTEM is a scalable framework for simulating large crowds and AI behaviors like the bustling market of Valdrest with impressive efficiency. Its data-driven design manages thousands of agents with minimal performance cost, making it ideal for creating realistic, dynamic populations in video games. It also supports Smart Objects and more complex interactions.
ML DEFORMER uses machine learning to deliver high-quality, real-time character deformations like Kelpie's muscle flexing. Trained on high-fidelity data, it learns to approximate complex deformations efficiently during gameplay, enabling realistic animations without the performance hit of traditional techniques.
UNREAL ANIMATION FRAMEWORK (UAF) powers advanced blending, state machines, and procedural animation workflows, ideal for scenes with many complex characters in motion, like Valdrest Market. The result? Smoother coordination, smarter runtime efficiency, and scalable performance.
FASTGEO STREAMING is a streaming system developed by CD PROJEKT RED and Epic used throughout the demo. It's optimized for quickly loading static geometry so it doesn't affect gameplay, using a lightweight method to register and unregister assets in graphics and physics scenes. You can see it best when we catch up to Ciri through the sweeping forest. There's no object pop-in or visual hiccups, just smooth, seamless world loading without compromising World Partition features like Runtime Data Layers or HLODs (The Hierarchical Level of Detail).
NANITE FOLIAGE uses Nanite's virtualized geometry system to render dense, detailed environments, like the forests around Valdrest, without compromising performance. It dynamically renders only the visible details at runtime, making it possible to populate vast landscapes with complex assets like trees and plants, efficiently and realistically.
MASS SYSTEM is a scalable framework for simulating large crowds and AI behaviors like the bustling market of Valdrest with impressive efficiency. Its data-driven design manages thousands of agents with minimal performance cost, making it ideal for creating realistic, dynamic populations in video games. It also supports Smart Objects and more complex interactions.
ML DEFORMER uses machine learning to deliver high-quality, real-time character deformations like Kelpie's muscle flexing. Trained on high-fidelity data, it learns to approximate complex deformations efficiently during gameplay, enabling realistic animations without the performance hit of traditional techniques.
