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Unreal Engine 5

inZOI is built on Unreal Engine 5 (UE5), Epic Games' latest game engine. Developer Krafton chose UE5 to deliver the game's highly detailed character models, realistic lighting, and dense residential environments. The engine's key rendering technologies, Nanite and Lumen, allow inZOI to render complex scenes with millions of polygons and dynamic global illumination without the heavy performance costs of traditional approaches. inZOI launched in Early Access on March 28, 2025 using UE 5.4, with an upgrade to UE 5.6 planned for the beta phase beginning in March 2026.

Nanite Virtualized Geometry

Nanite is UE5's virtualized geometry system that allows the engine to stream and render extremely high-polygon meshes in real time. Instead of artists manually creating multiple levels of detail (LODs), Nanite automatically determines which triangles are visible and at what resolution they should be rendered based on the camera's position and distance.

In inZOI, Nanite handles the dense residential environments, furniture, decorative objects, and architectural details that players interact with in Build Mode. When a player furnishes a home with dozens of detailed objects, Nanite ensures that nearby items display at full detail while distant objects are rendered at lower resolution, all without visible pop-in or LOD transitions. This is critical for a life simulation where players spend significant time in detailed indoor environments.

Lumen Global Illumination

Lumen is UE5's fully dynamic global illumination and reflections system. It calculates how light bounces between surfaces in real time, producing realistic indirect lighting, soft shadows, and accurate reflections without requiring pre-baked lightmaps.

For inZOI, Lumen is particularly important because of the game's dynamic time-of-day cycle and the ability for players to modify interior layouts. When a player moves a wall, adds a window, or changes the lighting fixtures in Build Mode, Lumen recalculates how light flows through the space in real time. Morning sunlight streaming through an east-facing window, artificial light bouncing off colored walls, and shadows shifting as the in-game day progresses are all handled by Lumen's real-time calculations.

Ray Tracing

inZOI supports both software and hardware ray tracing modes. Software ray tracing uses Lumen's screen-space and world-space tracing techniques that work on any modern GPU. Hardware ray tracing leverages dedicated RT cores on NVIDIA RTX and AMD RDNA 2+ GPUs for higher quality reflections and shadows.

In practice, the visual difference between the two modes in inZOI is relatively small (roughly a 6 to 8 percent performance difference), because Lumen's software implementation already produces high-quality results. Hardware ray tracing shows the most noticeable improvements in reflections on glass, water, and polished surfaces. Most players will find that software ray tracing provides an excellent balance of quality and performance.

Upscaling Technologies

inZOI supports three major upscaling technologies that render the game at a lower internal resolution and then reconstruct a higher-resolution image. These are essential for maintaining playable frame rates at high display resolutions, especially at 4K.

Each technology offers multiple quality presets (typically Ultra Quality, Quality, Balanced, Performance). Higher quality presets render at a higher internal resolution for sharper images but provide less of a performance boost. DLSS generally produces the best image quality when available, but FSR is the most accessible option since it works on any GPU.

Graphics Settings

inZOI provides extensive graphics customization through its settings menu. Players can adjust individual settings or choose from preset quality levels (Low, Medium, High, Ultra, Epic) that configure multiple options at once.

Performance Benchmarks

inZOI's performance varies significantly depending on hardware, resolution, and settings. The following benchmarks were gathered during the Early Access period (v0.1.x) and represent typical frame rates. Performance continues to be optimized in patches.

These numbers are approximate and will vary based on scene complexity, number of Zois on screen, and background tasks. Dense residential areas with many furnishings tend to be the most demanding scenes. Frame rates may improve with future optimization patches and the planned UE 5.6 upgrade.

VRAM Usage

inZOI is moderately demanding on VRAM (video memory). At 1080p with High settings, the game typically uses 6 to 8 GB of VRAM. At 4K with Ultra settings, VRAM usage can exceed 10 GB. Players with GPUs that have less than 8 GB of VRAM should use Medium or lower texture quality settings to avoid stuttering caused by VRAM overflow.

Smart Zoi and NVIDIA ACE

inZOI's Smart Zoi feature uses AI to generate dynamic dialogue and personality responses for Zoi characters. The AI component runs on a 0.5 billion parameter Mistral language model integrated through NVIDIA ACE (Avatar Cloud Engine). This is a gameplay AI system, not a rendering technology, but it leverages the GPU for inference when processing dialogue requests. Smart Zoi runs server-side and does not directly impact local rendering performance.

UE 5.6 Upgrade

Krafton has announced plans to upgrade inZOI from UE 5.4 to UE 5.6 during the beta phase, targeting March 2026. UE 5.6 includes improvements to Nanite (better support for foliage and translucent materials), Lumen (improved performance and quality), and general engine optimizations. The upgrade is expected to improve both visual quality and frame rates. Krafton has indicated this is one of the reasons for the extended beta period.

Fate Engine

The Fate Engine is not a rendering technology but rather inZOI's proprietary gameplay simulation system. It controls how Zoi characters make autonomous decisions, how life events unfold, and how the world simulation evolves. While the name might suggest a separate engine, the Fate Engine is a gameplay layer built on top of Unreal Engine 5, handling AI behavior, event scheduling, and the procedural narrative system.

System Requirements

For detailed hardware requirements, see the System Requirements article. In general, inZOI requires a modern quad-core CPU, 16 GB of RAM, and a GPU with at least 6 GB of VRAM for acceptable 1080p performance. An SSD is strongly recommended due to the streaming demands of Nanite geometry data.

Related Topics

• System Requirements for minimum and recommended hardware

• Smart Zoi for the AI dialogue system

• Fate Engine for the gameplay simulation layer

• Build Mode where Nanite/Lumen are most visible

• Graphics Settings for optimization guides