tools-unity-physics

Prevent Unity physics tunneling with continuous collision detection and sphere casts.

6|1|Updated Feb 6, 2026

Search Tags:#unity #physics #collision #tunneling #rigidbody #character-controller

Ready to run

npx skills add https://github.com/tjboudreaux/cc-plugin-unity-gamedev --skill tools-unity-physics

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: tools-unity-physics
Source: https://github.com/tjboudreaux/cc-plugin-unity-gamedev/tree/main/skills/tools-unity-physics
Command: npx skills add https://github.com/tjboudreaux/cc-plugin-unity-gamedev --skill tools-unity-physics

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Unity physics can produce floor penetration, tunneling, and unstable collision responses when moving fast or using simple controllers. This skill provides patterns to ensure reliable grounding, robust collision handling, and tunneling prevention.

Core Features & Use Cases

Continuous collision detection settings (e.g., Rigidbody collisionDetectionMode) to prevent fast objects from tunneling.
SphereCast ground checks and grounded state handling to improve stability of character movement.
Sub-stepping or stepwise movement strategies to handle high-speed motion without missing collisions.
Layer-based collision management for performance and correctness.
Practical patterns for projectile physics, character controllers, and rigidbody-based movement in Unity.
Troubleshooting guidance for common physics issues such as jitter, penetration, and missed collisions.

Quick Start

Integrate these patterns into your Unity project to achieve robust movement, reliable collisions, and tunneling prevention.

Frequently Asked Questions about tools-unity-physics

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I stop fast moving Unity rigidbody projectiles from tunneling through walls?▼

To prevent rigidbody tunneling in Unity, set the collisionDetectionMode to Continuous or Continuous Dynamic. This ensures fast-moving objects register collisions accurately instead of passing through colliders.

Why does my Unity character controller fall through the floor or jitter on slopes?▼

Character controller jitter and floor penetration occur due to unstable grounding. Using SphereCast ground checks instead of simple raycasts provides a wider contact area, stabilizing movement and ensuring reliable grounded state detection.

What is the best way to handle high-speed collision detection in Unity without missing impacts?▼

Sub-stepping is the best way to handle high-speed Unity collisions. By dividing motion into smaller stepwise movements, the physics engine processes intermediate positions, ensuring consistent collision responses and preventing missed impacts.

How do I use layer-based collision management to improve Unity physics performance?▼

Layer-based collision management improves Unity physics performance by filtering unnecessary collision checks. Configuring the Layer Collision Matrix prevents non-interacting objects from evaluating intersections, reducing computational overhead during runtime.

Can I apply these Unity physics patterns to both mobile and desktop projects?▼

Yes, these Unity physics patterns apply to both mobile and desktop projects. The continuous collision detection, SphereCast grounding, and sub-stepping techniques are designed to ensure robust movement across different platform scales.