vfx-and-particleslisted

# VFX and Particles ## Purpose Visual effects have two failure modes that dominate everything else: they cost far more than expected, and they do not read at the distance and speed players actually see them. Both are avoidable, and both are usually decided at authoring time rather than fixable later. The dominant cost is almost never particle count. It is **overdraw** — large transparent quads stacked on top of each other, each shading every pixel beneath. ## When to use - Authoring effects: impacts, abilities, muzzle flashes, weather, ambience. - Frame rate collapses during combat or in effect-heavy areas. - An effect is invisible, ambiguous, or misread at gameplay distance. - Effects feel unresponsive or mistimed relative to the action. - An effect leaks, persists after its owner is destroyed, or accumulates. ## When NOT to use - Surface appearance. Use `materials-and-shaders`. - Full-screen effects. Use `post-processing`. - Scene lighting. Use `lighting-design`. - General GPU cost outside effects. Use `gpu-optimization`. ## Required context | Fact | Why it matters | |---|---| | Engine, pipeline and version | Effect systems differ completely between engines | | Target platform and fill-rate budget | Mobile is fill-rate limited; effects are the first casualty | | Gameplay camera distance and field of view | Determines what actually reads | | Whether the effect conveys gameplay information | Readability requirements are much stricter if so | | Expected concurrent cou