Diffusion layers a soft-focus mist over the entire frame. Compared to bloom, its visual effect is distinct: while bloom adds raw brightness that can clip highlights to flat white, diffusion blends highlights gently so they halate outward smoothly, preserving delicate highlight texture without harsh clipping.
This effect replicates the look of cinematic mist diffusion filters attached to physical camera lenses — lowering contrast and softening speculars without defocusing the subject.
OriginalEffectControls
| Control | Range | Default | Effect |
|---|---|---|---|
| Intensity | 0 – 2 | 1 | Opacity and overall density of the diffuse mist |
| Radius | 0 – 1 | 0.85 | Spread distance of the glow from highlights |
| Threshold | 0 – 1 | 0.35 | Minimum brightness required to bloom (with smooth transition) |
Threshold and Soft Knee
Bloom defaults to a higher threshold (targeting sharp specular reflections); Diffusion defaults to 0.35, extending its reach into upper midtones to deliver a broader soft-focus appearance.
Threshold evaluation incorporates a soft knee curve that ramps smoothly into diffusion: lowering the threshold triggers diffusion sooner and more gradually across subtle tones; raising it confines diffusion strictly to prominent light sources.
Pairing With Bloom
Both effects can run simultaneously. In the rendering pipeline, Diffusion executes immediately after Bloom, applying its misting pass to an image that already carries bloom highlights. Bloom delivers specular luminescence while Diffusion provides subtle analog softening. For cinematic results, enable both with moderately reduced intensities.
For softening without visible specular glow, disable Bloom and run Diffusion alone. For crisp specular highlights without general image softening, use Bloom only — Diffusion intentionally softens overall image micro-contrast.
Transparent Stage Behavior
Like bloom, diffusion preserves the alpha channel. When running on a transparent stage, diffuse mist conforms strictly to the opaque pixels of avatars and models, preventing glow from bleeding onto your desktop.
Processing Order
Diffusion executes after bloom and before LUT color grading passes. As a result, the diffuse mist grades cohesively with the rest of the image rather than floating on top of the finished grade.
Last updated on November 3, 2026