Optimize LUMEN for VR in Unreal Engine 5

Name: Optimize LUMEN for VR in Unreal Engine 5
Uploaded: 2024-09-26T15:58:03.000Z
Duration: 1 h 14 min 6 s

Unreal Engine 5: Lumen, Nanite, and VR Optimization

Introduction to the Scene

The video discusses Unreal Engine 5's features, specifically Lumen and Nanite, in the context of VR applications.

The scene includes an African capsule tower interior, trees, and a movable sculpture for testing various functionalities.

Surrounding the scene are Nanite meshes that enhance visual fidelity.

Performance Metrics

Initial performance shows around 45 frames per second (FPS); switching to low-quality settings boosts FPS to 90.

Frame draw time is noted at 11 milliseconds; GPU time is at 9 milliseconds indicating potential for further optimization.

At high settings, FPS drops to around 45 due to reprojection techniques used when frame rates fall below headset refresh rates.

Understanding Reprojection

When the game cannot maintain 90 FPS, it halves the frame rate and reprojects frames to maintain perceived smoothness.

The Oculus app settings influence performance; adjusting refresh rates affects render resolution and overall experience.

Adjusting Settings for Optimal Performance

Changing from a recommended refresh rate of 90 Hz to 72 Hz improves render resolution but lowers frame rate.

Using console commands like stat FPS reveals current performance metrics; observed FPS drops to around 35 with increased calculation times.

Lumen Settings Optimization

All Lumen settings are managed through post-processing volume; adjustments include increasing view distance from default values.

Final gather quality is prioritized over scene lighting quality for better visual perception; initial tests show minor improvements in GPU timing after adjustments.

GPU Optimization Techniques

Adjusting Scene Lighting and Pixel Density

The speaker discusses the ability to increase scene lighting quality slightly, suggesting a maximum setting of 2 for optimal performance without compromising frame rates.

A command is introduced to reduce pixel density (R.pixel_density 0.5), which can help improve frame rates when experiencing low performance, although this specific adjustment did not yield positive results.

Lowering pixel density while maintaining high quality settings resulted in improved frame rates, reaching around 60 FPS with GPU times close to 12 milliseconds.

Further reduction of pixel density to 0.2 significantly decreased visual quality but allowed for near-optimal frame rates (72 FPS), demonstrating the trade-off between visual fidelity and performance.

The speaker notes that maintaining a pixel density of around 0.8 provides a stable experience despite occasional drops below 30 FPS, which is still perceived as smooth.

Quality Settings and Scalability

The combination of increased Lumen quality and high pixel density leads to performance hitches; adjustments are suggested to find an optimal balance between these settings.

Viewers are informed about downloadable content available in the video description, encouraging exploration of the discussed techniques.

Skillshare is promoted as a resource for designers looking to enhance their skills in various creative fields, including AI integration into design workflows.

An offer for a free trial on Skillshare is presented, aimed at helping aspiring designers develop their careers through specialized lessons and resources.

Command Setup for Quality Adjustment

The speaker explains how different scalability presets can be set using keyboard commands: pressing '1' sets low quality, '2' medium, '3' high, and '4' epic settings within the level blueprint setup.

Observations reveal that switching from low (1) to medium (2) drastically improves visual quality with added light and shadows; however, higher settings yield diminishing returns in terms of noticeable improvements.

Rendering Settings Overview

Discussion shifts towards rendering settings where increasing illumination quality correlates with lower frame rates; finding an effective balance is emphasized as crucial for performance optimization.

Understanding Instant Stereo and Dynamic Deviation

Instant Stereo Functionality

Instant stereo reuses pixels from one eye to the other, reducing the need for two screens and potentially increasing frame rates.

The dynamic deviation feature draws fewer pixels in peripheral vision while focusing more on where the user is looking; however, it may not function effectively without eye tracking.

Performance Observations

A medium setting for dynamic deviation is recommended for balanced performance.

Initial tests show a stable 36 frames per second (FPS), but issues arise with dynamic structures that transform during gameplay.

Visual Artifacts and Limitations

When using VR spectator screen mode, significant shimmering occurs in reflections due to pixel reprojection issues between moving objects.

Instant stereo works well when objects are static but fails with movement, leading to a decision to turn it off.

Exploring Unreal Engine's Substrate Materials

Introduction of Substrate Materials

Unreal Engine versions 5.1 and above introduce substrate materials as an experimental feature that can be enabled through project settings.

Users must be cautious as enabling substrate materials may lead to incorrect rendering if disabled later.

Performance Impact

After enabling substrate materials, performance drops slightly; transparent materials like glass may not render correctly.

As of September 30th, 2023, it's advised against using substrate materials with VR due to visual inconsistencies affecting user experience.

Optimizing Scene Settings for LumenVR

Anti-Aliasing Techniques

The anti-aliasing method should be set to temporal super resolution for optimal smoothing effects but may introduce ghosting artifacts.

Command Line Adjustments

Changing anti-aliasing methods via command line provides better insights into how settings will appear in VR compared to preview modes within the editor.

Understanding Anti-Aliasing Options

Anti-Aliasing Methods and Performance Insights

Exploring Anti-Aliasing Techniques

The speaker discusses the impact of different anti-aliasing methods on GPU performance, noting that with no anti-aliasing, the RGPU times are around 28-29 milliseconds.

Changing the anti-aliasing method to 1 results in similar or lower RGPU times while providing a slightly improved image quality. The left side of the screen shows foviation effects indicating resolution decrease.

Method 2 offers a smoother image without significantly increasing GPU time, which remains around 28 milliseconds. The speaker emphasizes that they are merely switching between various anti-aliasing techniques rather than enhancing quality.

Temporal Super-Resolution (TSR), identified as the most expensive method, is noted for its superior visual quality despite higher resource demands compared to other methods.

Performance Optimization and User Experience

The speaker highlights an interactive VR experience where users can manipulate objects within a structure, showcasing how light control enhances visual presentation.

A discussion on frame rates reveals that experiences can effectively run at 36 frames per second smoothed to 72 FPS without causing motion sickness, countering common beliefs about minimum frame rate requirements.

Motion sickness is linked more to hitches in frame delivery rather than low frame rates alone; smooth re-projection helps maintain user comfort during VR experiences.

Hardware Specifications and Expectations

The system used for testing includes an RTX 3080 graphics card with 10GB VRAM and an i7 10th generation processor. This setup demonstrates decent performance even without high-end specifications.