Interactive Struct Filler turns any USTRUCT into a guided, click-to-fill input flow — no boilerplate, no per-command UI code.

Hand the component a struct (an RTS command, an ability payload, a spawn request… anythinthe struct's fields and drives the player through one input "mode" per field — pick an

actor, pick a world point, pick a navmesh location, or your own custom mode — then hands struct, ready to execute, queue, or replicate.

It's the parameter-gathering front end for RTS commands, MOBA/ARPG ability targeting, building placement, tower defense, level/spawn tools, or any "click here, then here, then confirm" interaction.

WHY IT'S DIFFERENT

• Data-driven: the struct's shape defines the flow. Add a field → the wizard gains a step. Zero UI plumbing per command.

• One component, fully Blueprint: BeginFill / RouteInput / Cancel, plus OnCompleted / OnStepStarted / OnCanceled / OnMessage events. Drop it on your PlayerController and go.

• Extensible: subclass the mode base in C++ or Blueprint and call Commit() when satisfied. Explicit completion — no fragile "did the value change?" guessing that stalls on a legitimate (0,0,0) or false.

• Decoupled by design: dispatch goes through the IFillCommitSink interface or a delegate, so it slots into your command/ability system without dragging in dependencies.

WHAT'S INSIDE

• StructFiller (runtime core) — the fill engine, mode + LIFO stack, project settings, dispatch interface. Engine-only dependencies.

• StructFillerCommonModes — ready-made Pick Actor / Pick World Location / Pick Nav Location modes.

• StructFillerEditor — automation tests covering the full fill / cancel / abort lifecycle.

FEATURES

• Reflection-driven field walk over any FInstancedStruct

• Explicit Commit / Abort / IsComplete completion model

• Quick-cast (one-click) support

• Project Settings whitelist (struct → mode) + optional auto-registration

• Per-step and message events to drive your HUD

• Fully commented C++; README, Quick Start, and full API reference included

• 100% Blueprint-callable; author modes in Blueprint or C++

TECH NOTES

• Local / client-side input flow: it performs no replication and no authority checks — uploading the finished struct to the server is the host's responsibility (documented).

• Targets UE 5.4–5.7+: the StructUtils/InstancedStruct dependency is selected automatically per engine version in the build rules.

• No engine modification. Pure code plugin.

GET STARTED IN 3 STEPS

1. Add the StructFill component to your PlayerController.

2. Register a mode for each parameter struct (or use the Common Modes).

3. Call BeginFill(yourStruct) and bind OnCompleted.