Blueprints 101

4.1What Blueprints Are (And Aren't)

Blueprints are Unreal's visual scripting system: real gameplay classes built from nodes. For TAs, they're the fastest path to editor helpers, procedural placement tools, artist-facing actors, light rigs, spline meshes, modular kits, and prototypes. They're not magic C++. BP has per-node overhead, so logic running thousands of times per frame belongs in native code.

4.2Anatomy Of A Blueprint Actor

• Components panel - the actor's parts: meshes, lights, collision shapes, particle systems, arranged in a hierarchy.
• Event Graph - runtime logic driven by events: BeginPlay, Tick, overlaps, input. Execution flows along the white wire; data along the colored ones.
• Variables - typed, with the all-important Instance Editable flag that exposes them to level designers, and Expose on Spawn for spawn-time configuration.
• Functions vs Macros vs Events - functions return values and keep graphs tidy; custom events are for latent/async flows.

4.3The Construction Script - The TA's Playground

The Construction Script runs in the editor whenever an instance is placed or edited. This is TA playground territory: a fence that scatters posts along a spline, a room that resizes trim meshes, a light fixture that syncs emissive color to the light. Add Instance Editable variables and designers get sliders instead of hand-placing twenty meshes.

4.4Performance Discipline From Day One

• Turn Tick off by default. Most actors never need it. Event-driven logic (overlaps, timers, delegates) beats polling every frame.
• If you must tick, lower the Tick Interval - 10Hz is plenty for most gameplay logic.
• Avoid Get All Actors of Class in Tick - cache references once at BeginPlay.
• Casting to heavy BP classes creates load-time reference chains - prefer interfaces or component checks. A BP_Prop that casts to BP_GameMode drags the entire game mode (and everything it references) into memory with it.

The deep dive is in Performance -> CPU, Blueprints & Ticks.