Achieving Clean Mirror Reflection Without Hardware Ray Tracing (r.Lumen.HardwareRayTracing 0) in Unreal Engine

kam5251
Thu, 11 Dec 2025 06:10:51 +0000
Architectural and Design Visualization

Hello everyone,

I am currently working

on a real-time architectural visualization project (a virtual tour where the character can freely move around the house). My primary goal is to optimize performance by minimizing VRAM usage and boosting FPS, which necessitates avoiding hardware ray tracing.

My current settings are:

Rendering Mode: DirectX 11

Lumen Hardware Ray Tracing: r.Lumen.HardwareRayTracing 0 (Disabled)

When I set r.Lumen.HardwareRayTracing 1 (Hardware Ray Tracing Enabled), the mirror reflections are clean and accurate. However, with r.Lumen.HardwareRayTracing 0, the reflections (as shown in the second attached image) are highly noisy and blurry, failing to give a clean “mirror” look.

I have already looked into standard reflection techniques like Planar Reflections and Real-Time Scene Capture (Render Targets) by referring to various materials, including these examples:

Example Link 1

Example Link 2

Despite this research, I have not found a configuration that provides a clean, crisp, and high-quality mirror-like reflection that is also performant while satisfying the constraint of having r.Lumen.HardwareRayTracing disabled (set to 0) and running on DirectX 11.

What rendering features, console variables (Cvars), or material setups would you recommend to create clean, non-noisy reflections in this performance-optimized real-time environment? Specifically, what is the best approach when both SSR and the default Lumen software reflection yield unacceptable noise/blur?

Any advice on techniques that offer a good balance between visual quality and performance under these specific constraints would be greatly appreciated!

3 posts - 3 participants