a5c-ai/unity-physics

Unity Physics Skill

Physics system configuration and implementation in Unity.

Overview

This skill provides capabilities for implementing physics-based gameplay using Unity's physics systems (PhysX 3D and Box2D 2D).

Capabilities

Rigidbody Configuration

• Configure mass, drag, constraints
• Set up continuous collision detection
• Handle interpolation modes
• Manage sleep thresholds

Collision Detection

• Configure colliders and triggers
• Set up collision layers and masks
• Handle collision events
• Implement compound colliders

Raycasting

• Perform raycasts and spherecasts
• Use overlap tests
• Handle layer filtering
• Batch physics queries

Physics Settings

• Configure fixed timestep
• Set up solver iterations
• Handle physics materials
• Manage auto-sync transforms

Prerequisites

• Unity 2021.3+
• Physics module (built-in)

Usage Patterns

Rigidbody Setup

public class PhysicsObject : MonoBehaviour
{
    private Rigidbody rb;

    void Awake()
    {
        rb = GetComponent<Rigidbody>();
        rb.interpolation = RigidbodyInterpolation.Interpolate;
        rb.collisionDetectionMode = CollisionDetectionMode.Continuous;
    }

    void FixedUpdate()
    {
        rb.AddForce(Vector3.forward * 10f, ForceMode.Force);
    }
}

Raycasting

public bool CheckGround(out RaycastHit hit)
{
    return Physics.Raycast(
        transform.position,
        Vector3.down,
        out hit,
        1.1f,
        groundLayer,
        QueryTriggerInteraction.Ignore
    );
}

Best Practices

1. Use FixedUpdate for physics
2. Avoid scaling colliders at runtime
3. Use layers for filtering
4. Profile physics queries
5. Consider Physics.autoSyncTransforms

References

• Physics Documentation