Asymptomagical - Multiplayer Systems & Hex-Grid Tech Sample (UE5, C++)

In-editor hex grid generation and edit workflow.

Asymptomagical is a UE5 multiplayer group project.
My main focus in this codebase is networked gameplay architecture, especially a replicated hex-grid built on Instanced Static Meshes, alongside a deep C++ Gameplay Ability System (GAS) integration and clean session/user infrastructure.

• Engine / Stack: Unreal Engine 5 (C++ & Blueprints), GAS, CommonUI, Online Subsystem
• Focus areas: multiplayer-ready systems, bandwidth-efficient replication, reusable GAS framework, editor-friendly workflows

Note on assets: The /Content folder is intentionally not included in this public snapshot.
The project uses licensed assets (e.g., marketplace/Fab content) and the full content directory is too large to distribute here.
This repository is therefore focused on the C++ systems and architecture; it is not directly runnable without providing your own assets.

Project demos (YouTube):
Short clips showcasing key systems from this project.

• Hex grid editor utility / ISM instance workflow – in-editor grid generation and per instance transform modification.
• FastArray grid replication + gameplay tags demo – delta replication of tiles with tag-driven visual/state updates.

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Core concepts

• Replicated Hexagonal Grid using Fast Array delta replication
  • Server-authoritative tile state replicated via FFastArraySerializer
  • Rendering through UInstancedStaticMeshComponent, driven by per-tile data
• GAS as the backbone for character actions and stats
  • PlayerState-owned ASC for players, pawn-owned ASC for AI
  • Data-driven AbilitySet pattern for loadouts
• Decoupled user/session management via GameInstanceSubsystems
  • Clean interface over Online Subsystem (create/find/join sessions)
  • Async user/login init separated from gameplay
• Modern UI framework using CommonUI
  • Activatable widgets + widget stacks for robust navigation/input routing

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Architecture highlights

1) Hex Grid + Network-Optimized ISM Replication (HexagonalGrid/)

The hex grid is managed by a single server-authoritative actor, avoiding one-actor-per-tile overhead.

Key idea: tile state lives in a replicated fast array, so clients receive only deltas for tiles that change.
This keeps bandwidth low and scalable even for large boards.

• AHexGrid
  • Owns the authoritative tile array (FTileDataArray) replicated using FFastArraySerializer
  • Exposes gameplay entry points like SetTagsOnTile(TileIndex, NewTags)
  • Editor generation utilities (CallInEditor) for rapid iteration:
    CreateHexGrid(), RaiseRim(), RandomizeHeight(), Clear()
• Rendering
  • Uses engine UInstancedStaticMeshComponent (ISMC) to render all tiles as instances
  • Visual state (materials/colors) is driven by replicated tile data + tags on clients
• Replication lifecycle (example)
  1. Ability targets a tile → calls SetTagsOnTile() on server
  2. Tile data mutates in TileArray
  3. Fast Array computes a delta and replicates only that tile’s change
  4. Clients update local tile data and patch the corresponding ISMC instance

Note: UHexInstancedStaticMeshComponent exists as a thin placeholder from an earlier design;
the current implementation uses the standard ISMC directly for clarity and stability.

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2) Gameplay Ability System (GAS) (AbilitySystem/)

GAS is integrated in C++ as a reusable, multiplayer-safe foundation.

• Custom GAS spine
  • AsymAbilitySystemComponent – project ASC hub
  • AsymGameplayAbility – shared base for costs, cooldowns, activation patterns
  • AsymAttributeSet – replicated stats with clamping + effect handling
  • AsymAbilitySet – data asset bundling loadouts (abilities/effects/attributes)
• ASC ownership best practice
  • Players: ASC on AsymPlayerState for persistence across respawns
  • AI: ASC on AsymCharacter (pawn-owned) for simplicity

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3) EsotericUser / EsotericSession Plugins (Plugins/EsotericUser/)

These subsystems handle identity + sessions as pure infrastructure, independent of gameplay (inspired by Lyra’s Common User pattern). The name prefix comes from another project I initially developed the plugins for.

• UEsotericUserSubsystem
  • GameInstance-lifetime user/login state
  • Async init action to avoid blocking the game thread
• UEsotericSessionSubsystem
  • Clean interface over OSS session APIs
  • UI-friendly methods for create/find/join

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4) CommonUI Framework (UI/)

Uses Unreal’s modern UI stack model.

• UAsymActivatableWidget / UAsymActivatableWidgetStack
  • Modular screens pushed/popped with correct input routing
  • Supports keyboard/mouse/gamepad cleanly

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Additional tooling note (not included)

Alongside this project I prototyped a separate ISM/HISM instance editing tool in a custom editor mode.
It’s excluded from this public snapshot because it’s being cleaned up and stabilized as a standalone editor utility.

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Credits / contributions

• Programming & systems: Nicolas Martin
• Design: Vladimir Eck, Alexander Kharkovski

Team development was done in Perforce; this repository is a curated public snapshot.