Volumetric Light
The alternate volumetric-lighting path renders light shafts and fog using Sky Atmosphere's Volumetric Lighting settings. Open Control Panel > X:VFX > Volumetric Light for its controls.
This documents the current local source. Runtime correctness and performance still require validation in the intended project; source availability alone is not a performance result.
Requirements
- The fork's Visibility Buffer frame path.
- A Sky Atmosphere component with Volumetric Lighting enabled.
- Virtual Shadow Maps disabled.
Enable and Queue Selection
x.VisibilityBuffer.VolumetricLighting | Behavior |
|---|---|
0 | Disabled |
1 | Preparation, shadow min/max and integration on async compute; composite on graphics |
2 | All passes on graphics |
While this alternate path renders, it disables UE height fog, volumetric fog, local fog volumes and light shafts. Treat it as an alternate route, rather than adding its output on top of all stock fog systems.
Quality and Lighting Controls
| Console variable | Purpose |
|---|---|
x.VisibilityBuffer.VolumetricLighting.Quality | Resolution and sun integration steps |
x.VisibilityBuffer.VolumetricLighting.MaxLocalLights | Maximum contributing local lights |
x.VisibilityBuffer.VolumetricLighting.MaxShadowedLights | Maximum shadowed local lights |
x.VisibilityBuffer.VolumetricLighting.EarlyShadows | Render shadow depths early to allow integration overlap |
x.VisibilityBuffer.VolumetricLighting.Debug | Diagnostic output |
x.VisibilityBuffer.VolumetricLighting.DebugScale | Diagnostic display scale |
Quality levels are 0: quarter resolution/16 sun steps, 1: half resolution/24 steps, 2: half resolution/32 steps, and 3: half resolution/48 steps.
Scheduling the Existing Fog Route
When using the existing volumetric-fog route in the visibility-buffer frame, x.VisibilityBuffer.AsyncVolumetricFog selects its queue policy:
| Value | Scheduling |
|---|---|
0 | Graphics |
1 | Async setup beside shadow depths |
2 | Async after shadow depths |
3 | Async setup, scattering on graphics |
x.VisibilityBuffer.VolumetricFogInterleave exposes interleaving. These settings schedule the existing fog route; they do not enable the alternate volumetric renderer. The routes are not active together.
See Atmosphere for the fork's atmosphere defaults and Flow for simulated smoke/fog volumes.