Epic Games says it is using AI tools to "develop code and features" for Unreal Engine, including core engine components like the D3D12 rendering layer

AI is now writing core engine code for Unreal Engine, making game development faster and more efficient.

Epic Games has confirmed it is using AI tools, including models like Claude Code and Codex, to develop code and features for Unreal Engine, specifically for Unreal Engine 6 and Unreal Editor for Fortnite (UEFN). Executive Vice President of Development Marcus Wassmer stated that AI is assisting across a wide range of development tasks, leading to significant improvements such as the elimination of long-standing non-deterministic cooking bugs and accelerated shader compression, which reduces patch sizes. The company has also rewritten a substantial part of the D3D12 rendering layer, completing the work in about a week, and is using AI for automatic monitoring and root cause analysis of PC stability issues in Fortnite. Epic views AI development as essential for faster iteration, improved modularity, and modernization of the engine, believing that software developed with AI will ultimately be superior and more responsive.

Epic Games' integration of AI into core engine development signifies a significant shift in how major game engines are built, moving beyond AI for assistance to AI for direct code generation and architectural changes. This approach, particularly the rewrite of the D3D12 rendering layer and the ability to undertake large-scale refactors, suggests a future where complex engine components can be developed and optimized at unprecedented speeds. The focus on modularity and the ability to strip out unneeded features indicates a path toward more customized and efficient game development pipelines for studios of all sizes.

The company's embrace of AI, despite potential skepticism, positions Unreal Engine as a leader in adopting advanced development methodologies. By actively using AI for debugging, stability monitoring, and even automatic fix generation, Epic is not only accelerating feature delivery but also enhancing the reliability and performance of its engine. This proactive stance suggests that other engine developers and game studios will feel increasing pressure to adopt similar AI-driven workflows to remain competitive in terms of development speed and product quality.