Volumetric Nebula - QtFRED Help

# Volumetric Nebula

Opens via Editors › Volumetric Nebula.

Configures the volumetric nebula renderer. Unlike the classic nebula in the Background Editor, the volumetric nebula is rendered as a true 3D volume with light scattering, emissive glow, and procedural noise shaping.

## Key fields

Field | Description
--- | ---
Enabled | Adds the volumetric nebula to the mission. Uncheck to disable without losing settings.
Model | POF model that defines the outer boundary shape of the nebula volume. The mesh must be watertight; multiple disjunct meshes are allowed as long as their polygons do not intersect.
Position (X, Y, Z) | World-space position of the nebula volume.
Color (RGB) | Primary color the nebula is rendered with.

## Rendering

Field | Description
--- | ---
Opacity | Target translucency - the maximum opacity the nebula reaches at full depth. Cannot be set to 0.
Opacity distance | Distance in metres a viewer must be inside the nebula before it reaches its target opacity.
Render quality steps | Number of steps used to accumulate nebula density along each ray. Higher values reduce banding on objects inside the volume; primarily affects frame rate.
Resolution | Resolution of the nebula's 3D density texture, stored as a power of 2 (5–8 recommended). Higher values cost more VRAM.
Oversampling | Oversampling factor for the 3D texture (1–3). Each increment quadruples loading time but reduces edge banding, especially at lower resolutions. Primarily affects load time.
Smoothing | Controls how softly the hull POF's edges blend into the surrounding nebula. Expressed as a fraction of the nebula size.
Henyey-Greenstein coefficient | Controls light scattering direction. Values greater than 0 produce a cloud-like shine-through effect; values less than 0 produce a highly reflective nebula. Practical range is roughly 0.05–0.75.
Sun falloff factor | Scales how the sun's illumination falls off with nebula depth. Values greater than 1 make the nebula's interior brighter than physically accurate; values less than 1 make it darker.
Sun quality steps | Number of steps taken toward the sun per nebula slice when computing shadowing. Higher values reduce light/shadow banding; primarily affects frame rate.

## Emissive

Field | Description
--- | ---
Emissive light | Intensity of the emissive glow added by light sources inside the nebula. Higher values produce brighter emissives.
Intensity | Controls how quickly an emissive light source widens inside the nebula. Larger values spread the glow more broadly even where there is little nebula to obscure it.
Emissive light falloff | Corrects emissive alpha near the source. Values greater than 1 darken the emissive close to its origin, producing a more even spread; values less than 1 brighten it near the origin, making it more intense at the center.

## Noise

Procedural noise is layered on top of the base volume to break up uniform density and create wispy internal structure.

Field | Description
--- | ---
Enable noise | Toggles procedural noise on or off without losing the noise settings.
Color (RGB) | Tint color applied to the noise layer.
Scale base | Size of the primary noise layer in metres. The ratio between Scale base and Scale sub should have a large denominator to avoid visible harmonic patterns in the result.
Scale sub | Size of the secondary noise layer in metres.
Intensity | Overall strength of the noise effect.
Resolution | Resolution of the noise 3D texture, stored as a power of 2 (5–8 recommended). Higher values cost more VRAM.
Set Base Noise Function | Not yet implemented. Will allow a custom ANL noise expression to replace the default base noise layer.
Set Sub Noise Function | Not yet implemented. Will allow a custom ANL noise expression to replace the default sub noise layer.