Unreal Engine 5
The Witcher IV runs on Unreal Engine 5.6, replacing CDPR's proprietary REDengine, with a tech demo running at 60 FPS on base PS5.
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CD Projekt Red announced in March 2022 that The Witcher IV would use Unreal Engine 5, developed by Epic Games. This replaced the proprietary REDengine that powered The Witcher 2, The Witcher 3, and Cyberpunk 2077.
CDPR had used REDengine for over a decade. Moving to Unreal Engine 5 meant retraining the development team on new tools, but it also opened access to Epic's ongoing R&D, a larger hiring pool of developers already familiar with Unreal, and faster iteration. CDPR described it as a strategic partnership rather than a standard licensing arrangement.
The June 2025 tech demo at the State of Unreal ran approximately 14 minutes. It was played live by cinematic director Kajetan Kapuscinski, with narration from game director Sebastian Kalemba and Epic Games' Wyeth Johnson.
CDPR explicitly stated: "A first look at the advanced technology powering The Witcher 4, but not The Witcher 4 itself." The demo was purpose-built to show UE5 capabilities, and the final game may look different.
Component | Requirement |
|---|---|
Engine version | Unreal Engine 5.6 |
Hardware | Base PlayStation 5 (not PS5 Pro) |
Frame rate | 60 FPS with ray tracing (Lumen in hardware tracing mode) |
Internal resolution | Approximately 900p average, with dips to the mid-800s |
Upscaling | Temporal Super Resolution (TSR) to an estimated 1440p output |
Item | Description |
|---|---|
FastGeo Streaming | Co-developed by CDPR and Epic for fast environment loading without visible loading screens |
Nanite Foliage | Extremely high polygon vegetation (arriving in UE 5.7) that scales automatically by distance |
MetaHuman with Mass AI | Over 300 individually animated NPCs on screen in Valdrest, each behaving independently |
Motion Matching | Advanced animation for Kelpie's horse movement, blending gaits based on speed and terrain |
Chaos Flesh | Physics-based skin and muscle deformation using machine learning, visible in Kelpie's shoulders during galloping |
ML Deformer | Facial animation technology that shows fatigue and emotion on Ciri's face |
Ray tracing | Real-time Lumen lighting at 60 FPS |
The cinematic reveal trailer from December 2024 was rendered in a custom build of Unreal Engine 5 running on an NVIDIA GeForce RTX 5090 (which was unannounced at the time). The trailer was produced in collaboration with Platige Image, the studio behind all previous Witcher game cinematics. CDPR stated it was "powered by the same tech that The Witcher IV is built on, using assets and models from the game itself."
CDPR engineers have contributed tools and optimizations back to the engine, including FastGeo Streaming. Epic has provided dedicated technical support for CDPR's requirements. The relationship is described as a close development partnership, with both companies benefiting from shared R&D.
At GDC 2026, NVIDIA and CD Projekt Red presented a second tech demo focused on RTX Mega Geometry foliage technology. Unlike the June 2025 demo, which showcased town environments and character animation, the GDC 2026 demo highlighted the natural world.
The demo rendered approximately 60 million plants, roughly 1 million trees, and more than 200 distinct plant species across a 5x5 kilometer map area. Some larger trees exceeded 10 million polygons each. Pine needles, leaves, and branches were modeled as full geometry rather than flat billboard textures, creating a level of foliage detail not previously achievable in real-time rendering.
Specification | Detail |
|---|---|
Plants rendered | Approximately 60 million |
Trees rendered | Approximately 1 million |
Plant species | Over 200 |
Map area | 5x5 kilometers |
Max tree polygons | Over 10 million per tree |
RTX 5090 (4K, DLSS Quality) | Approximately 80 FPS |
RTX 4070 (1440p, DLSS Quality) | Approximately 58 FPS |
Beyond what was shown in the State of Unreal 2025 demo, CDPR and NVIDIA have confirmed support for several additional technologies in The Witcher IV.
DLSS 4: NVIDIA's latest upscaling and frame generation technology is supported
Real-time Path Tracing: Full path-traced lighting is confirmed as an option for high-end PC hardware
FastGeo Streaming: Developed jointly by CDPR and Epic Games, this system handles efficient streaming of environment geometry for the open world
RTX Mega Geometry: Allows rendering of extremely high-polygon assets like trees and foliage without the performance cost of traditional polygon rendering
CDPR confirmed a new show at Unreal Fest 2026, scheduled for June 16 through 18 in Chicago. Additional Witcher IV footage running on Unreal Engine 5 is expected at the event.