Celestial Vault causes Volumetric Clouds to flicker on macOS (Metal)

General Issues and Bug Reporting (Unreal Engine)
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Summary

On macOS, adding a CelestialVaultDaySequenceActor causes volumetric clouds to flicker continuously. The issue affects not only Celestial Vault’s own cloud component but also any regular VolumetricCloud actor placed in the level.

The problem disappears when:
r.VolumetricRenderTarget.Mode=1
or
r.VolumetricRenderTarget.Mode=2

Only Mode=0 exhibits the issue.

What Type of Bug are you experiencing?

Rendering (Graphics / Niagara)

Steps to Reproduce

  1. Create a new level.
  2. Add CelestialVaultDaySequenceActor.
  3. Observe flickering clouds.
  4. Alternatively, add a standard VolumetricCloud actor and disable the one inside Celestial Vault.
  5. The standard cloud also flickers.
  6. Execute r.VolumetricRenderTarget.Mode 2.
  7. Flickering disappears.

Expected Result

Volumetric clouds should render consistently without flickering when using CelestialVaultDaySequenceActor. The presence of Celestial Vault should not affect the rendering stability of standard VolumetricCloud actors, regardless of the selected VolumetricRenderTarget mode.

Observed Result

Volumetric clouds continuously flicker when a CelestialVaultDaySequenceActor is present in the level on macOS. The issue also affects regular VolumetricCloud actors, even if Celestial Vault’s own cloud component is disabled. Setting r.VolumetricRenderTarget.Mode to 1 or 2 immediately eliminates the flickering.

Affects Versions

5.8

Platform(s)

Mac

Video