Representation-First Particles, Trails, and Effects

Own GPU-resident object- and world-space effects: spawn, motion, lifetime, compaction, draw representation, depth/blend behavior, and scene-linear HDR emission. Route viewport history to $threejs-dynamic-surface-effects, weather accumulation to $threejs-rain-snow-and-wet-surfaces, authored event motion to $threejs-procedural-motion-systems, and shared post ownership to $threejs-image-pipeline or $threejs-bloom.

When an effect consumes collision, forcing, or exchange owned by another system, close this local handoff before step 1: