Optimised Volumetric Smoke, Gas & Carving (URP + Built-in)

Optimised Volumetric Smoke is a real-time, raymarched smoke and gas system for Unity. Instead of flat billboard particles, it renders genuine 3D volume that you can walk into,

  see lit and shaded from every angle, and shoot straight through. It's built from the ground up for performance, so you can actually use it in a shipping game.

  KEY FEATURES

  • Real raymarched volumetrics: soft, lit, animated smoke with self-shadowing, gravity slump, soft edges and an adjustable density floor.

  • World conformance (CS2-style): clouds flood-fill the air they can actually reach, blocked by your level geometry, and spread by volume so they flow down corridors instead of

  clipping through walls.

  • Bullet & explosion carving: shoot healing tunnels through smoke and blast spherical holes with grenades, with organic, noise-distorted edges. One-line API.

  • Seamless overlapping smoke: overlapping clouds composite without popping and merge into one continuous volume in a single unified pass, with no seams. Works in both URP and

  Built-in.

  • Heavily optimised: half-resolution rendering, a baked 3D-noise texture, distance-based adaptive step count, frustum culling, early-out integration and near-zero per-frame

  allocations. Spam clouds and watch the framerate hold.

  • Grenade-ready: timed clouds that fade in, hold, then dissipate realistically (thinning into drifting wisps with a gentle shrink), plus an IsInside() check for your own

  gas-damage logic.

  FULLY CUSTOMISABLE

  Everything is exposed in the Inspector: colour, shadow colour, density, opacity, noise scale, edge softness, gravity, lumpiness, wind, boil speed, light direction, step count,

  soft depth, bounds roundness and more. One shader, many looks: dial in thick opaque combat smoke, thin see-through coloured gas, or anything between. Smoke and Gas presets

  are included to start from. Live-tune it and watch it change in real time.

  SUITED TO MANY GENRES

  Designed with tactical and competitive shooters in mind (CS-style smokes, gas grenades, vision-blocking cover), but equally at home in horror, stealth, survival, and

  atmospheric or cinematic scenes. If your project needs believable, interactive smoke, gas, fog or steam, it fits.

  ONE PACKAGE, BOTH PIPELINES

  Works in URP and the Built-in Render Pipeline from a single import, with the same feature set on both, including the seamless overlapping-smoke compositing. The correct

  renderer is selected automatically and the URP-only code excludes itself on Built-in, so there are no errors either way. A one-click Setup window enables the half-resolution

  performance mode for your pipeline.

  EASY TO USE

  Drag in a ready-made prefab, use the GameObject menu, or add the Smoke Volume component to any object. Carve it from your own weapons with SmokeVolume.CarveBullet(...) /

  CarveSphere(...). Full source is included, no DLLs.

  WHAT'S INCLUDED

  • Drop-in Smoke Volume component + carve API

  • Universal smoke shader (URP + Built-in) and optional half-res renderers

  • Ready-made Smoke / Gas / Smoke Grenade prefabs

  • Demo scenes (one per pipeline) with a fly camera, throwable grenades, shooting, and an FPS HUD

  • Full PDF user guide + script reference

  REQUIREMENTS

  • Unity 6 (6000.0) or newer recommended (Unity 2023.3+ is required for URP's half-resolution mode, which uses RenderGraph; Built-in has no version requirement)

  • URP (enable Depth Texture) or the Built-in Render Pipeline

  • The demo uses the Input System package (the asset itself does not)

  • No third-party Asset Store dependencies, all source included