Mist

Mist adds height fog and volumetric fog to Unity 6 and the Universal Render Pipeline. Based on HDRP’s fog implementation, it is adapted for URP Render Graph and supports the Universal Renderer’s Forward, Forward+, Deferred, and Deferred+ paths.

Documentation

Core Features

• Height fog with density, height, start-distance, and range controls. Fog color can use a constant HDR color, the active skybox, or a custom cubemap, with tint and mip controls.
• Froxel-based volumetric fog with directional, point, and spot lights, shadows, URP light cookies, and GI from Adaptive Probe Volumes or the ambient probe. Global controls include albedo, emission, and anisotropy.
• Per-light overrides for contribution, intensity, shadow strength, and temporal evaluation, plus punctual-light fade distance and source radius. Current Frame Only mode excludes rapidly changing lights from temporal history.
• Local fog volumes with oriented box or ellipsoid bounds, per-face or radial fades, distance fading, priority, and hierarchy-scale controls. Supports Overwrite, Additive, Multiply, Min, Max, and Subtractive blending.
• Checkerboard volumetric lighting evaluates stable lighting on alternating froxels each frame and fills skipped samples from valid reprojected history, reducing lighting evaluations. This optional mode requires temporal reprojection and zero anisotropy.
• 3D texture masks with RGB scattering tint, alpha density, and per-axis tiling and scrolling. A Fog Volume Shader Graph target supports procedural or texture-driven color and density.
• Transparent Shader Graph integration enabled automatically for URP Lit and Unlit targets. An explicit Transparent Fog node and an HLSL helper support custom integration. Unity’s built-in URP transparent shaders are not supported.
• Screen-space multiple scattering approximation that softens already-fogged scene color before transparent rendering, with adjustable strength and quality.
• Temporal and spatial denoising using reprojection, Gaussian filtering, both, or neither. Includes history weighting, rejection, and invalidation for detected camera discontinuities and key projection or buffer changes.

Quality and Performance

Mobile, VR, Balanced, Quality, and Cinematic presets provide starting points. Balance mode derives resolution from a quality budget; Manual mode exposes screen resolution and depth-slice count directly.

Volumetric distance, slice distribution, denoising, and lighting can be tuned independently. Height fog can run without volumetrics, and volumetric lighting can be restricted to directional lights.

Additional controls include:

• Full, Half XY, or Quarter XY local-volume voxelization, retaining the depth-slice count.
• Conservative depth optimization to skip occluded volume and lighting work when URP Depth Priming is active.
• Optional asynchronous compute for volumetric lighting and filtering.
• Independent lighting and history storage formats: RGBA16F or split R11G11B10 + R16F. Split storage uses 25% fewer bytes for the affected textures, with reduced radiance precision and an extra texture access.
• Per-camera light and volume limits, priority-based volume selection, and configurable memory warnings.
• Compute shader variant stripping based on included URP configurations and stripping settings.

Optional optimizations depend on hardware support and should be profiled on target devices.

Diagnostics

A Rendering Debugger panel exposes raw, temporal, and filtered lighting; final fog; extinction; punctual lights; local-volume contribution and IDs; froxel layout; and effective light radius.

Controls include depth-slice inspection, light and volume isolation, and temporal or mask-scrolling freezes. Scene-view debug gizmos show bounds, fades, mask flow, slots, and light radii. Opt-in runtime statistics report buffer dimensions, estimated texture memory, counts, formats, and quality settings.

Included Samples

The Volumetric Package Manager sample includes a demonstration scene, reusable prefabs, 3D textures, Shader Graph examples, and procedural-noise subgraphs.

• Ground smoke, fumes, and local cloud-like fog
• Animated texture masks and point-lit volumes
• Volume blending and procedural shapes
• Screen-space multiple scattering
• Transparent surfaces with fog enabled and disabled

Requirements and Platform Notes

• Unity 6000.3 and URP 17.3.0
• Universal Renderer with Render Graph enabled

Volumetric fog requires compute shaders, 3D textures, and R16G16B16A16_SFloat load/store and linear-sampling support. Local volumes additionally require floating-point render-target blending. On supported graphics backends, height fog remains available when volumetric requirements are unmet.

Screen-space multiple scattering has separate format requirements and is skipped for incompatible MSAA configurations. Compact storage falls back to RGBA16F when unsupported.

URP Compatibility Mode, the 2D Renderer, OpenGL Core, and OpenGLES are unsupported. Mobile volumetrics require suitable Metal or Vulkan hardware.

Mist evaluates fog on Base cameras and leaves Overlay cameras unfogged. XR-aware rendering targets single-pass XR on compatible devices.