Tier 2 Series 103

103A: Collision vs. Trigger

Pilot Record
Student Profile
"A submarine doesn't crash into a sonar ping; it detects it. If your AI treats a "Zone of Influence" (like radiation or gravity) as a solid brick wall, you've created Physics Friction. A skilled Engineer audits for Interaction Mode."

The Concept: Interaction Modes

Unity Physics has two distinct ways of handling "Touch":

* **Collision:** Physical impact. Physics forces are applied. The object bounces, stops, or rolls. Used for Walls, Floors, and Debris.
* **Trigger:** Ghost-like detection. The object passes through, but a code event is fired. Used for Zones, Pickups, and Sensors.
Red Flag Detected

The AI Trap: "The Solid Ghost"

You ask the AI: "Make the drone pick up the fuel pack when it touches it."

// AI-Generated Code: Physical Impact
void OnCollisionEnter(Collision other) {
    // Audit Fail: The drone will physically bounce off the fuel pack
    // BEFORE this code runs. It feels clunky and amateur.
    CollectFuel();
}

This is "Physics Friction." The player expects to glide through the power-up, but instead, they crash into it like a crate. A professional pilot ensures "Pickups" are non-physical Triggers.

Elite Telemetry

Research shows "Elite" teams achieve 15% faster lead times by keeping AI on a "very tight leash."

  • Small Batches Solving one problem at a time prevents logic drift.
  • Modular Design Localizing the "blast radius" of AI changes.
  • Tight Loops Rapid iteration with constant code review.

The Pilot's Correction

Corrective Protocol
// Corrected: Smooth and Ghost-like
void OnTriggerEnter(Collider other) {
    // The drone flies right through, collecting the fuel instantly.
    CollectFuel();
}
Your Pilot Command
> Direct the AI to use Hash IDs for Animator parameters to improve performance.
Next Mission
The Collision Matrix