Introduction

Intermact is an interactive math visualization platform built on React Three Fiber. Starting as an "interactive Manim alternative" (v0.1), it expanded through the v0.2 math toolbox into a full 2D interactive narrative system; v1.0 further delivers PCG, 3D, export/embed, and plugin extensibility. The same program can orchestrate narrative animation, support live parameter tuning, let viewers drag to explore, and embed into web pages and handouts.

Packages are on npm (@intermact/core, @intermact/react v1.0.0). To install in your app, see Getting started · Use in your app (npm); to hack on this repo, see "Run from source" on the same page.

What problem does it solve?

Pain point	Intermact approach
Manim offline rendering is slow and costly to iterate	Real-time rendering in the browser — change code, see results immediately
Traditional animation libraries are hard to make interactive	Retained-mode seekable timeline + Signal/derived reactive layer
Experiment logic coupled to rendering	core has no framework dependency; headless evaluation and testing in Node/Worker
Output limited to video	Web-native serialization, snapshot/video export, Web Component embed (v1.0)

What can v0.1 do? (Phase-1)

• Declarative 2D primitives: circle, ellipse, rectangle, arc, polygon (with holes), Bézier, line segment, arrow
• Create stroke/fill reveal, Fade, Move, Rotate, Scale
• Coordinate systems: Cartesian domain, abs/rel/fit transforms, polar coordinates, getAxes to register axis objects
• Reactive: signal / derived / valueTracker / tweenSignal, bound to Leva
• React entry: <IntermactCanvas program={...} /> + timeline overlay controls

What can v0.2 do? (Phase-2 · math toolbox)

• Scale: linear / log / pow / time scales, axis ticks and formatting
• Math constructs: NumberPlane, FunctionGraph, Riemann sum, tangent, Matrix/Table/Brace, DecimalNumber
• Morph: arc-length / anchor / matching / cross-fade; group2D part keys and transformMatchingTex
• Text and LaTeX: OpenType outlines + MathJax SVG; stroke-by-stroke writing; vector multi-size glyphs
• Interaction: draggable control points/values, precise hit-test, explorable derivative exploration
• Layout and Inspector: nextTo / arrange / fitTo; React Inspector for scene tree and signal debugging

Documentation structure

• Guides: concepts and code examples for users (this directory)
  • Core capabilities (v0.1): program, timeline, geometry, rendering, animation, coordinates, reactive
  • Math toolbox (v0.2): Scale, constructs, Morph, text/LaTeX, interaction, layout
• API Reference: TypeDoc-generated symbol docs (overview with Phase-1/2 entry tables)
• Packages: @intermact/* layer responsibilities and dependency rules
• Examples: index aligned with the examples/ demo gallery
• Project: milestone roadmap and v0.1 / v0.2 / v1.0 acceptance checklists

For the full interface contract and revision history, see dev-docs/design.md and dev-docs/dev-roadmap.md.