Putting it all together

Designing Dynamic Scenarios with Runtime Spawner

Overview

The power of Runtime Spawner comes from combining three systems:

  1. Runtime Spawner – the foundation. Handles normal enemy spawning (randoms, waves, zones).

  2. Spawn Director – controls pacing via Intensity Profiles. Escalates or calms pressure.

  3. Special Encounter Manager – injects high-impact moments (special enemies, minibosses).

Together, these systems create adaptive, replayable encounters where pacing and threats feel directed — much like Left 4 Dead’s AI Director, GTFO’s mission waves, or Payday’s special forces spawns.


Core Loop

The flow of decisions can be summarized like this:

[SpawnDirector sets pacing]

[Runtime Spawner emits regular enemies at tuned rate]

[SpecialEncounterManager checks rules]

[Special enemies spawn under specific conditions]

[Players experience a dynamic mix of baseline + spikes]

Example Scenarios

1. Left 4 Dead – Rolling Pressure with Specials

  • Spawner: baseline zombie trickle

    • Global spawn window: 3–6s

    • Alive cap: 15

  • Director: intensity steps escalate over time

    • Step 0: Calm → 5 alive cap, long spawn windows

    • Step 1: Escalation → 10 alive cap, shorter windows

    • Step 2: Finale → 20 alive cap, rapid spawns

  • Specials: rare threats injected periodically

    • Flanker (Hunter): appears if HP < 70%, step 1+

    • Pinner (Smoker): requires no LOS, long cooldown

    • Tank: cooldown 180s, pressure > 50, step 2 only

Result: A constantly shifting mix of baseline zombies and surprise specials that adapt to player state.


2. GTFO – Timed Waves + Pressure Specials

  • Spawner: waves triggered by alarms or objectives

    • Wave rate multiplier: scaled by profile step

  • Director: AutoByTime

    • Every 60s, step escalates

  • Specials: triggered when pressure spikes

    • Giants spawn only if many enemies are already alive

    • Sleepers spawn at long distance, require no LOS

Result: Waves build tension on alarms, and specials ensure punishment if players take too long.


3. Payday – Specials as Counters

  • Spawner: constant baseline cops

  • Director: step progression tied to objectives

    • Step 0: Break-in = low intensity

    • Step 1: Bag carry = higher intensity

    • Step 2: Escape = peak pressure

  • Specials: tactical counters

    • Cloaker: appears when a player strays > 20m from group

    • Bulldozer: HP > 50% and pressure high

    • Shield: spawns tagged "Frontline" zones

Result: Specials act as role disruptors, forcing the team to adapt mid-heist.


Design Tips

  • Use Director for the baseline curve – How much pressure should players feel at each stage?

  • Layer Specials sparingly – Specials work best when rare, surprising, and conditional.

  • Mix step ranges + cooldowns – This prevents “stacking” and keeps pacing varied.

  • Experiment with tags – Spawn tags let you design roles for specials: flanks, ranged threats, boss zones.


Takeaway

By combining these three systems, you can design encounters that:

  • Escalate over time without manual scripting

  • Respond to player health/pressure

  • Mix baseline enemies with rare but memorable specials

This is the foundation of emergent scenario design — and can be reused across survival, horde, wave-defense, and co-op shooters.

Last updated