Comet Core & Tail VFX URP

Comet Core & Tail VFX is a complete procedural comet for Unity 6 and URP: a lit, noise-displaced core plus a glowing tail that is generated entirely on the GPU. No particle system, no CPU simulation, no mesh — the tail is one procedural draw call per stream, and every quad is built inside the vertex shader from its vertex ID.

WEBGL DEMO → (requires a WebGPU-capable browser, desktop or mobile; Chrome enable-unsafe-webgpu in chrome://flags/)

The tail is authored, not simulated. A curve defines its silhouette as a surface of revolution — a rising line gives a cone, a bump gives a spindle, a falling curve gives a plume — and particles are placed either on the shell of that shape or through its volume. Speed, lifetime, drag, spread and size are ranges, so a stream stays alive and varied forever with nothing to spawn, pool or warm up: the tail is complete on the very first frame. Gradients and curves are baked into a small lookup texture when you edit them, so tuning color, size or silhouette is instant and free at runtime.

Streams are independent. Stack a wide dust plume, a narrow ion jet and a bright halo on one object, each with its own material, tilt, roll, seed, particle count and HDR gradient. The tail blends additively, so with HDR and Bloom enabled it glows exactly as bright as you author it.

The core is a full URP PBR shader with metallic or specular workflow, normal map, emission, and animated 3D value noise displacement that runs identically in the forward, shadow, depth and depth-normals passes — shadows and depth-based effects stay glued to the deformed surface.

Everything renders in the Scene view without entering Play mode, and complete C# and HLSL source is included: no Shader Graph, no VFX Graph, no black boxes. The whole tail system is two files and 325 lines, so extending it means editing code you can actually read, not rewiring a graph.

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REQUIREMENTS

✅ Unity 6 — built and tested on 6000.3

✅ Universal Render Pipeline (Built-in RP and HDRP are not supported)

✅ Shader model 4.5: Windows / Linux (D3D11, D3D12, Vulkan), macOS and iOS (Metal), Android (Vulkan only — remove GLES3 from the graphics API list)

⚠️ WebGL 2.0 cannot run the tail; a Web build requires Unity's experimental WebGPU backend

ℹ️ HDR must be enabled on the URP Asset and the Camera for the glow to work

ℹ️ The included camera helper uses the Input System package