API reference

The complete surface.

Every option, method, attribute, and catalog entry. The forces, presets, conditions, and formations pages are generated from the engine's own catalog, so they can't drift from the code you install.

Reference

createField & options The entry points and every FieldOptions knob. Core requires a host; @fundamental-engine/vanilla and <field-root> wire browserHost() for you. FieldHandle The object every entry point returns — drive the field at runtime. Declarative authoring reference Everything written in markup, in one place — the [data-body] contract, the forces, the feedback channels, conditions, formations, render/overlay vocab and both custom elements, each with a generated JS · Swift · Kotlin support row. Imperative API reference Everything reached from code, in one place — createField and its options, the whole FieldHandle, the sampling and observable reads (query, snapshot, diff, replay, projections), the capability-scoped agent view, policy and budgets, the body handle and the event bus, each with a generated JS · Swift · Kotlin support row. data-* attributes Every attribute a body reads, and which force reads which. Forces (37) The full catalog — law, attributes, and example per force. Presets (9) Whole compositions as one attribute. No new engine code. Conditions, formations & modes The orthogonal axes — when, field-wide, and how it draws. Types Core types (Body, Particle, Force, Env) and platform types. API stability The frozen 0.x public surface, the experimental surface, and the compatibility rules — enforced by pnpm check:api. @fundamental-engine/dom DOM participation: the FrameScheduler + six registries (measurement, state, feedback, relationships, visual bindings, overlays) + lintPlatform(). Platform parity matrix Which FieldHandle methods ship on Three.js, Swift, and Kotlin — generated from the ports, with the current gaps named. Not full parity: the JS surface has grown since the ports last caught up. Metrics & diagnostics The observability surface: inspectBudget, energyReport, lintPlatform, and the live --field-* feedback channels. Platform utilities withFlip (FLIP animation), allocateAttention (conserved budget), threadOverlay, bindFieldNav, QualityGovernor, textBodies, and headlessHost. Cookbook — patterns by task The depth layer beside this reference: signals-first and contained fields, bindData at scale, reading and instrumenting, conditions and formations, the workbench, performance tuning, chrome and accessibility, and framework interop — every pattern with an example that actually runs.

At a glance. 37 forces · 9 presets · 6 conditions · 5 formations · 12 render modes · 4 palettes — one shared field runtime, host-native participation, a DOM adapter for the web, and a core with zero runtime dependencies.