t1k:unity:rendering:vfx-graph

Field	Value
Module	`rendering`
Version	`3.1.7`
Effort	`medium`
Tools	—

Keywords: particle, unity, VFX Graph, visual effects

How to invoke

/t1k:unity:rendering:vfx-graph

Unity VFX Graph — GPU Particle Effects

Visual Effect Graph reference for Unity 6 (com.unity.visualeffectgraph). GPU-based, node-graph particle system.

VFX Graph vs Particle System

Feature	VFX Graph	Particle System
Simulation	GPU (compute shader)	CPU
Particle count	Millions	Thousands
Node graph editor	Yes	Inspector-based
Mobile support	Requires compute shaders	Full support

Rule: Use VFX Graph for high-count effects (rain, fire, magic, debris). Use Particle System for simple mobile-friendly effects.

C# Integration

using UnityEngine.VFX;

public class VFXController : MonoBehaviour {
    [SerializeField] VisualEffect vfx;
    VFXEventAttribute hitAttr;   // cache once, reuse per-call

    void Start() {
        vfx.Play();
        vfx.Stop();
        vfx.Reinit();

        vfx.SetFloat("SpawnRate", 100f);
        vfx.SetVector3("EmitPosition", transform.position);
        vfx.SetVector4("Color", new Vector4(1, 0, 0, 1));
        vfx.SetTexture("MainTex", myTexture);
        vfx.SetBool("EnableTrails", true);

        // CACHE event attribute once — never call CreateVFXEventAttribute() per-event.
        hitAttr = vfx.CreateVFXEventAttribute();

        int aliveCount = vfx.aliveParticleCount;
    }

    void OnHit(Vector3 hitPos) {
        // Reuse cached hitAttr — overwrite values per-call.
        hitAttr.SetVector3("position", hitPos);
        hitAttr.SetFloat("damage", 50f);
        vfx.SendEvent("OnHit", hitAttr);
    }
}

Key Gotchas

Requires compute shaders: Won’t work on low-end mobile GPUs (OpenGL ES 3.0 minimum)
Exposed properties must be explicitly exposed: Right-click property → “Expose” in graph
Event attributes not cached: Create VFXEventAttribute once, reuse
SRP only: Requires URP or HDRP — won’t work with Built-in RP
Particle System prefab warning: VFX Graph assets are .vfx, not .prefab

→ Full architecture (Spawn/Init/Update/Output contexts), events, property binders, effect recipes (Fire/Rain/Explosion/Magic), performance tips: references/architecture-and-recipes.md

unity-urp — Render pipeline integration
unity-shader-graph — Custom VFX shaders
unity-mobile — Mobile VFX optimization

Reference Files

File	Contents
architecture-and-recipes.md	Spawn/Init/Update/Output contexts, events, property binders, effect recipes, performance tips, gotchas