Custom Rigid-Body Engines
Bespoke rigid-body simulators with position-based or impulse-based solvers tuned to your accuracy and stability requirements — far past what generic engines offer.
2D Physics Engine Development
Custom 2D Physics Engines for Games, Sims & Robotics
We engineer custom 2D physics engines, collision detection systems, constraint solvers, and deterministic simulation runtimes for games, interactive education, robotics, biomechanics, and bespoke simulators — when Box2D, Chipmunk, or Matter.js do not fit your accuracy, determinism, or footprint requirements.
Deterministic · CCD · SIMD-accelerated · WASM-ready
C++Rust · TS · WASM
SATGJK · EPA · CCD
DeterministicFixed-step solvers
WASMWeb · Mobile · Desktop
Physics Engines We Build
From bespoke rigid-body solvers to deterministic networked engines and soft-body simulations — engineered when off-the-shelf hits a wall.
Constraint & Joint Solvers
Custom revolute, prismatic, distance, weld, and rope constraints, plus motor constraints for vehicles, characters, and machinery — stable at large mass ratios.
Collision Detection
SAT, GJK + EPA, AABB / SAP / dynamic BVH broadphases, continuous collision detection (CCD), and TOI calculations — pick what your scene actually needs.
Soft-Body & Cloth Effects
Position-based dynamics (PBD), Verlet integration, mass-spring systems, and finite-element approximations for 2D cloth, rope, jelly, and fluid-ish effects.
Game-Ready Integrations
Bindings for Unity, Godot, Phaser, PixiJS, and custom game frameworks — with editor tooling, debug renderers, and scene serialization.
Robotics & Education Sims
Deterministic 2D simulators for robotics teaching, control-loop tuning, biomechanical research, and STEM products — reproducible runs and exportable trajectories.
Industries We Serve
EdTech, game studios, robotics, biomechanics, industrial simulation, and visualisation products — wherever physics drives the interaction.
EdTech & STEM
Robotics
Biomechanics
Game Studios
AR / Visualisation
Industrial Sim
Logistics Sim
Trading Sims
Stack & Primitives
Modern systems languages, web runtimes, linear algebra libraries, and reference engines we benchmark against.
C++17/20Core
RustCore
TypeScriptWeb Binding
WebAssemblyWeb Runtime
EmscriptenToolchain
wasm-bindgenToolchain
Eigen / glmLinear Algebra
SIMD (SSE / NEON)Acceleration
Box2D (reference)Reference
Chipmunk2D (reference)Reference
Unity / GodotIntegration
PixiJS / PhaserWeb Integration
Our Physics Engine Process
A six-step rhythm so engines ship with the stability, determinism, and performance your scene actually needs.
Use-Case & Constraints
We map your scene scale, body counts, accuracy, determinism, platform mix, and what off-the-shelf engines fail at — before committing to a custom build.
Solver & Integrator Design
Integration scheme (semi-implicit Euler, Verlet, RK4), solver (PGS, NGS, PBD), broadphase, and CCD strategy — designed for your accuracy/stability/footprint trade.
Implementation & Tests
Engine implementation with property-based tests, stability tests on stacks and large mass ratios, determinism tests, and end-to-end perf benchmarks.
Performance & Determinism
SIMD optimisation where applicable, cache-friendly layouts, fixed-point math when determinism matters, and exhaustive replay-equivalence tests.
Bindings & Integration
Bindings to your game engine or web framework — Unity, Godot, Phaser, PixiJS — with debug rendering, scene serialization, and editor tooling.
Support & Tuning
Retainer for new shape types, joints, perf tuning, and ports to new platforms (mobile, WASM, console) — your engine stays alive as your product grows.
Why Choose Hendoi for Physics Engines
Six commitments that separate engines that ship 60fps from engines that explode on the first stack of crates.
Real Math Background
Physics is unforgiving — small mistakes cause explosions, jitter, or non-determinism. Our engineers bring real numerical methods background, not "we tried Box2D once".
Honest Build/Buy Advice
Box2D, Chipmunk2D, Matter.js, and Rapier are excellent. We will tell you when one of them fits — and when your accuracy, determinism, or footprint needs justify a custom engine.
Performance Engineering
SIMD broadphase, cache-friendly body and constraint layouts, dynamic BVH tuning, and benchmark-driven design. We aim at your real scenes, not toy demos.
Determinism When You Need It
Fixed-step integrators, deterministic broadphase, optional fixed-point math, and replay equivalence tests — for networked games and reproducible simulations.
Senior Engineers Only
Physics engines reward experience. Our seniors have shipped engines into games, EdTech simulators, and research-grade robotics workflows.
Transparent Engagement
Weekly demos with debug renderers, direct access to engineers, signed SOWs with explicit accuracy and stability targets, and predictable burn.
Engagement Models
Pick the shape that matches whether you are validating an idea, committing to production, or maintaining a shipped engine.
Engine Prototype Sprint
A 4-6 week sprint to build a focused prototype matching your scene shape, with stability tests, perf benchmarks, and a written build/buy recommendation.
- Focused scene prototype
- Stability + perf benchmarks
- Build/buy recommendation
Production Engine Build
Coordinated programme to design, implement, integrate, and ship a production engine with bindings, debug tooling, and tests across your target platforms.
- Engine + bindings + tools
- Determinism + perf budgets
- Platform-tuned builds
Engine Maintenance Retainer
Predictable monthly retainer covering new shapes, joints, perf tuning, platform ports, and incident response for production simulations and games.
- New shapes + joints
- Perf tuning
- Platform ports + on-call
Real-World Use Cases
Representative custom physics engines engineered for STEM, games, robotics, multiplayer, industrial visualisation, and biomechanics.
STEM Physics Simulator
Custom 2D engine for an EdTech product teaching Newtonian mechanics — deterministic replays, exportable trajectories, and an authoring tool for teachers to build scenes.
Mobile Casual Game Engine
Lightweight C++ engine compiled to ARM and WASM for a casual mobile/web game — 60fps on entry-level Android, with stable stacking and frictionless tuning UI.
Robotics Teaching Sim
Deterministic 2D robotics simulator for a higher-education programme — differential-drive, sensors, control-loop hooks, and Python bindings for student experiments.
Networked Multiplayer Sim
Rollback-friendly fixed-step engine for a competitive multiplayer game — deterministic across platforms, with state snapshotting and replay tooling.
Industrial Conveyor Sim
Bespoke 2D engine for a factory-floor visualisation product — simulates 5000+ packages on conveyors with friction, jamming, and downtime modelling.
Biomechanics Research Engine
Research-grade 2D engine for gait analysis — joint constraint solvers tuned for human-scale forces and motion capture data import.
Frequently Asked Questions
Common questions game studios and simulation teams ask before committing to a custom physics engine.
When should I build a custom 2D physics engine versus using Box2D, Chipmunk2D, Matter.js, or Rapier?
Off-the-shelf engines are excellent for 90% of games and simulations. Custom engines pay off when you need very specific accuracy, deterministic networked replay, tiny footprint on embedded targets, exotic constraint types, or research-grade numerical control. We benchmark off-the-shelf first and document the gap honestly.
How do you ensure determinism?
Fixed-step integration, deterministic broadphase ordering, deterministic constraint-solver iteration counts, optional fixed-point math, and replay-equivalence tests across hardware. We test determinism on x86, ARM, and WebAssembly platforms.
Which languages and platforms do you target?
C++17/20 and Rust for cores. We compile to native desktop (Win/Mac/Linux), mobile (iOS/Android), WebAssembly for browsers, and embedded targets. TypeScript or C# bindings are common for game engines.
Can you integrate with Unity, Godot, or web game frameworks?
Yes — we provide bindings (P/Invoke for Unity, GDExtension for Godot, JS/TS wrappers for Phaser/PixiJS), plus debug renderers and scene serialization tooling.
Do you support soft-body, cloth, or fluid effects?
Yes — position-based dynamics (PBD) for cloth and soft bodies, particle systems with surface tension for fluid-ish effects, and mass-spring + finite-element approximations where accuracy matters.
How long does a custom 2D physics engine take to build?
A prototype matching your scene: 4-6 weeks. A production engine with bindings, tools, and tests: 4-8 months. Maintenance retainers run indefinitely after that.
What does a custom physics engine cost?
Significant — typical production builds run into six figures (INR) depending on scope. We make sure the build/buy maths actually pencil out before recommending a custom build — many projects end up choosing tuned off-the-shelf.
Will I own the engine source code?
Yes — full source, build system, test suite, and benchmarks. You own everything. We can provide ongoing maintenance under a retainer, but you are never locked in.