Unreal Engine 5.1 Preview is released

Lumen improvements in Unreal 5.1 include:

• Improved performance optimizations in High scalability mode with the goal of achieving 60 fps on consoles
• Improved support for foliage
• Reflections on Single Layer Water
• Support for high-quality mirror reflections on translucent surfaces
• Support for nDisplay (SWRT and HWRT)
• Initial support for split-screen (SWRT only); performance characteristics still TBD
• Experimental: Hardware Ray Tracing (HWRT) in Vulkan - Surface cache lighting only, no support yet for Hit Lighting
• Many stability, quality, and bug fixes

The Path Tracer continues to add support for more engine features, including:

• Exponential Height Fog and Sky Atmosphere Fog
• Decals
• Single Layer Water
• Per-instance custom data
• Light functions
• Multi-GPU rendering

Nanite improvements:

The primary focus of Nanite for 5.1 is the addition of a programmable rasterization framework, opening the door to features such as masked materials, two-sided foliage, pixel depth offset, and world position offset. Please note that the exact feature list and expected stability and performance characteristics are still TBD.

• Other updates include:
• Nanite material switch in the Material Editor
• Additional diagnostic and debug modes
• Many quality and performance improvements

GPU Lightmass Improvements:

• Ongoing feature compliance updates, including stationary skylights, static IES lights, and per-light cast shadow flag
• Irradiance Cache and First Bounce Ray Guiding have better behavior and higher quality from the same settings
• Improved denoiser results at low light levels
• Additional quality and performance improvements
• On-Demand Shader Compilation compiles only the shaders needed to render what is seen on screen in the editor, and optionally during platform development iteration. The result is a drastic reduction of shaders being compiled, especially on large projects.