Exploring the depths of the new Sky & Atmosphere system | Unreal Engine

Summary

This video provides an in-depth exploration of Unreal Engine's sky and atmosphere rendering features, focusing on new capabilities in version 4.26. The speaker demonstrates how to dynamically control the environment through Blueprints, including simulating weather changes, eclipses, and a rotating starry sky. They also cover improvements in real-time skylight capture and volumetric clouds, highlighting performance-friendly solutions. Key features include smoother atmospheric transitions, realistic cloud rendering, and enhanced sky lighting with minimal performance overhead, making these advancements ideal for both cinematic and real-time applications.

Takeaways

• 😀 Blueprints allow for dynamic sky changes like updating Rayleigh scattering for different weather conditions in Unreal Engine.
• 🌅 Directional light can be controlled with Blueprints, including creating effects like eclipses and moon rotation.
• 🌟 In Unreal Engine 4.26, the construction script can now be updated during Control-L live updates, improving workflow efficiency.
• 🌍 A workaround for real-time updates in 4.25 involved using Blueprint widgets for continuous sky changes in the editor.
• ☀️ The 'MultiScatteringLUT HighQuality' CVar improves the realism of light scattering in both space and on planetary surfaces.
• 🌌 Stars are blended into the sky with a post-process material, dynamically appearing during the night and blending seamlessly with the environment.
• 🌑 Post-process materials are used to simulate the rotation of stars around the planet, and fading them in based on the brightness of the sky.
• 🌅 Real-time skylight capture was previously performance-heavy in earlier Unreal versions, but 4.26 introduces a performance-efficient real-time skylight capture feature.
• ☁️ Volumetric clouds in 4.26 offer fully 3D clouds that interact with the sun, casting shadows and god rays across the world.
• 🌞 The new volumetric clouds come with automatic god rays and environmental darkening, creating a more dynamic and realistic atmosphere.
• 🌍 Unreal Engine 4.26 introduces advanced features like scalable sun luminance, volumetric cloud rendering, and per-pixel atmosphere transmittance for more immersive simulations.

Q & A

What is the main challenge addressed in the video regarding sky and atmosphere rendering?

The main challenge is ensuring that sky and atmosphere adjustments work entirely within the viewport, especially when simulating dynamic elements like storms or eclipses. This was particularly difficult prior to updates in Unreal Engine 4.26.

What improvement is introduced in Unreal Engine 4.26 for working with construction scripts?

In Unreal Engine 4.26, construction scripts can be used when Control-L (real-time updates in the editor) is active, addressing a limitation present in 4.25 where construction scripts did not update when Control-L was enabled.

How is the simulation of an eclipse implemented in this example?

The simulation of an eclipse is achieved through Blueprint scripting. The sun's visibility is hidden behind the moon, creating a darkened atmosphere during the eclipse, which is dynamic and controlled within the viewport.

What workaround is suggested for updating the sky in 4.25 when Control-L is not supported in construction scripts?

For 4.25, the workaround involves using a Blueprint widget that can update sky effects on tick, even within the editor, to simulate dynamic atmospheric changes.

What does the 'MultiScatteringLUT HighQuality' CVar do?

Enabling 'MultiScatteringLUT HighQuality' improves the quality of light scattering, making both space and surface light interactions look more realistic, enhancing the overall visual fidelity of the sky and atmosphere.

How are stars blended into the scene, and how does the system react to the camera's position?

Stars are blended into the scene using a post-process material, which fades them in depending on the sky's brightness. The system also checks if the camera is in space or on the surface to adjust how the stars are displayed, fading them in where the sky is dark enough (such as during sunset).

What is the main benefit of the new 'real-time skylight capture' feature in 4.26?

The 'real-time skylight capture' feature in 4.26 allows for smooth and performance-friendly skylight updates in real time, with minimal impact on performance. This replaces the previous method, which was heavy on resources and caused noticeable performance hitches.

What is the significance of volumetric clouds introduced in 4.26?

Volumetric clouds in 4.26 offer a highly detailed, dynamic cloud system that reacts to environmental changes like sun movement. The clouds interact with the environment, casting shadows, creating god rays, and can even be explored in 3D space.

How do volumetric clouds enhance the realism of the atmosphere?

Volumetric clouds enhance realism by providing 3D, interactive cloud systems that simulate realistic light interactions, including god rays and shadows that affect the entire world as clouds move across the sky.

What are some of the advanced settings and features available in the 4.26 sky and atmosphere system?

Advanced features in 4.26 include the new volumetric cloud rendering, real-time skylight capture, dynamic sun luminance, and improved sky and atmosphere shadowing. These features enhance visual fidelity and performance while providing greater artistic control over the scene.