Tensio — High-Performance DOTS Rope & Chain Physics

Tensio is a high-performance, physics-based rope and chain simulation framework engineered specifically for the Unity game engine. Built on Extended Position Based Dynamics (XPBD), Tensio delivers rock-solid, physically accurate, and interactive flexible-body simulations suitable for everything from indie titles to AAA games and industrial simulations.

By leveraging Unity’s Data-Oriented Technology Stack (DOTS) — including the C# Job System, Burst Compiler, and Mathematics (SIMD) library — Tensio executes all core physics, collision detection, and procedural mesh generation asynchronously across worker threads, maintaining a smooth 60+ FPS main game loop with Zero Garbage Collection (0B GC Alloc) allocations per frame.

Unity Discussions & Support

Have questions, feature requests, or want to discuss integration strategies? Visit the Tensio Unity Forum Official Thread or email devbayk@gmail.com.

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🚀 Why Tensio?

Simulating flexible objects like ropes, cables, winches, and chains has historically challenged real-time graphics and physics engines. Traditional mass-spring systems frequently suffer from “super-elasticity” (excessive stretchiness) or explosive instability when stiffness parameters are dialed up.

Tensio solves this fundamental constraint problem using XPBD (Extended Position Based Dynamics):

• Infinite Stiffness: Simulate totally inextensible steel cables and railway chains without jitter or numerical drift.
• Physical Compliance: Accurately model elastic materials such as bungee cords, suspension tethers, and rubber bands.
• Unconditional Stability: Geometric distance and attachment constraints are solved unconditionally, preventing mesh explosions even under extreme gravitational or kinetic stress.
• Predictable Time Steps: Physics sub-stepping handles high-speed dynamic motions seamlessly without clipping through geometry.

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⚡ Core Capabilities

⚛️ Multi-Threaded Physics

PBD constraint solver running in parallel on worker threads via Unity's Job System & Burst Compiler.

🔗 Dual Rendering Pipeline

Procedural Catmull-Rom tube meshing (`RopeRenderer`) and GPU-instanced rigid links (`RopeChainRenderer`).

💥 3-Tier Collision System

Standard World SphereCast, ultra-fast analytical SDF Proxy Colliders, and spatial hash Inter-Rope self collisions.

✂️ Real-time Interaction

Interactive slicing and splitting (`RopeCutter`), dynamic motor winches (`RopeWinch`), and anchor pinning.

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🧭 Documentation Map

Explore the detailed documentation chapters:

1. Installation & Dependencies — Unity version requirements (2022.3+ LTS), package dependencies, and Burst settings.
2. Quick Start Guide — Create and simulate your first rope in under 60 seconds with interactive pinning.
3. Core Components:
   • Rope Controller — Master component for simulation, particles, and physics parameters.
   • Rope Renderer — Continuous 3D procedural tube mesh generation and UV tiling.
   • Rope Chain Renderer — High-performance GPU-instanced rigid chains.
   • Interaction Tools — Winching systems, mouse cutting, and real-time tearing.
   • Rope Audio — Physics-reactive procedural audio loops and impact triggers.
4. Editor Toolbars:
   • Bezier Point Window — Scene View floating toolbar, relaxation solver, and shape modifiers.
   • Make Colliders Rope-Ready — One-click Unity Collider to Tensio Proxy Collider conversion.
5. Advanced Topics:
   • Rendering Optimization & Batching — Single-draw-call batching for thousands of ropes.
   • Collision Systems — World SphereCast vs. Analytical SDF Proxy vs. Spatial Hash.
   • LOD System — Distance-based CullingGroup switching between 3D Mesh, Line, and Suspended states.
   • Grappling Hook Case Study — Complete player grappling hook implementation breakdown.
6. C# Scripting API Reference — Public methods, properties, and events for runtime scripting.
7. Frequently Asked Questions (FAQ) — Performance tuning, mobile tips, and jitter troubleshooting.