Bring AAA-Grade Atmosphere to Your URP Game
Volumetric fog is one of the defining visual signatures of modern AAA titles think the drifting haze of The Witcher 3's swamps or the smoke-choked corridors of Dead Space. The technique behind that look low-resolution raymarching stabilized by temporal reprojection is exactly what powers BT-Spectral Fog, rebuilt from the ground up for URP and Unity 6's Render Graph.
No brute-forcing every pixel. No choosing between "looks good" and "runs well." Spectral Fog raymarches at a fraction of your screen resolution and reconstructs full-quality atmosphere through a temporal and depth-aware pipeline, the same category of trick the big studios rely on, running comfortably on hardware they never had to think about.
🎯 Core Rendering Systems
QuadMarch — Quarter-Res Raymarch Engine
- Raymarches at quarter (or half) resolution instead of full screen, cutting the raw cost of volumetric lighting dramatically
- Transmittance-based early exit skips samples the eye would never notice anyway
- Every knob — resolution, step count, blur passes, lives on the Volume Profile, no code changes needed
GhostGuard — Temporal Stabilization
- Motion-vector reprojection rebuilds detail the low-res march alone can't capture
- Neighborhood clamping kills ghosting on fast camera turns and disocclusion, no smeary trails behind moving objects
- Screen-edge fade removes the seam artifact that plagues naive reprojection
EdgeWeave — Depth-Aware Blur & Upsample
- Smooths noise without smearing fog across silhouette edges
- Thin foreground objects stay crisp against distant fog instead of bleeding into it
🌫 Lighting & Atmosphere
Sun & Local Light Scattering
- Directional light shafts through fog with full shadow and anisotropy control
- Point and spot lights scatter through the volume too, drop a component on any light and it just works
- Adaptive Probe Volume support lets ambient GI color the fog naturally (Unity 2023.1+)
PocketFog — Local Fog Volumes
- Drop box or sphere volumes anywhere for a foggy cave mouth, a swamp patch, a magic mist, independent of the global height fog
- Frustum-culled automatically, so scenes with dozens of pockets don't pay for the ones off-screen
Animated Density Noise
- Wind-driven turbulence breaks the flat "gradient fog" look into something that actually reads as volumetric
🛠 Built for Real Production, Not Just Demos
HeightSync — One-Click Auto Fit
- No more guessing world-space Y values for every new scene. One button reads your terrain and level geometry and sets the fog's floor and ceiling for you.
- The single biggest time-sink with height fog, solved in one click.
Clean Tabbed Inspector
- General, Lighting, and Quality split into tabs instead of one endless list of sliders
Dual Render Path
- Full Unity 6 Render Graph support, with a Compatibility Mode path for URP 2022.3+ same feature set, either way
🎮 Runs Everywhere URP Does
- Scales from VR/mobile presets to full desktop fidelity from a single profile
- Perspective and orthographic cameras both fully supported
What You Get
- Complete, commented source code, nothing obfuscated, nothing locked behind a black box
- Full documentation covering every parameter
