LCM Nav3D: Documentation

The LCM Nav3D welcome screen

Stuck, or want to talk to the author? → Discord: discord.gg/nXkpD6uaBG. Verify your purchase in #get-help for direct support, bug tracking and early builds. More UEDEV plugins and resources: uedevlabs.github.io. Want to try it before buying? The free playable demo packs all 18 demo maps into a standalone Windows build. Everything on this site is also available as PDFs — the full manual and the quick start — for reading away from the editor.

Built for production

LCM Nav3D is an industry-leading volumetric navigation system for Unreal Engine: heavily optimised, production-grade, and built for AAA-scale projects. It ships complete C++ source, is fully exposed to Blueprint, and is engineered so that the expensive parts stay off your frame budget. The specifics:

Engineered for	How
GPU acceleration	GPU voxelization with automatic CPU fallback when no GPU is present - so it degrades gracefully instead of failing. A GPU path solver is experimental, currently in research validation, and ships in a future free update
Crowd scale	10,000+ agents through the Mass Entity ECS with LOD-culled rendering, where a UActor AI agent costs roughly 50 µs/tick once it has a controller, movement component and behaviour tree
Off the game thread	Asynchronous pathfinding throughout, with a callback on completion rather than a blocking query
Frame budget	Explicit frame-budget controls, and dynamic-obstacle updates coalesce dirty regions into a single window (`r.LcmNav.DynObs.CoalesceMs`, default 33 ms) instead of restamping per event
Memory	A sparse octree, so cost is driven by how cluttered your level is rather than how large it is - open sky is nearly free
Determinism	Same input, same output, every time - which is what makes replays, lockstep multiplayer and automated tests reproducible
Large worlds	World Partition and streaming support, with a bake path and a coarse skeleton for long-range routing before the detail exists
Not a black box	A health check that reports anything that would stop agents moving, an auto-tuner that measures candidate voxel settings against your real routes, and a Gameplay Debugger category costing roughly 10 µs

Supported on Unreal Engine 5.2 to 5.8, Windows 64-bit and Linux. Every claim above is documented in the chapter it belongs to - start with Core Concepts, or see Nav3D vs Recast if you are deciding whether you need volumetric navigation at all.

Start here

→ LCM_Nav3D_QuickStart.pdf - 13 pages. Install it, understand the five settings that matter, and have a pawn flying through 3D space in your own level. About forty-five minutes end to end. This is the only document most people need to read from front to back.

Everything else is there for when you need it:

If you want to...	Open	Size
Get running	LCM_Nav3D_QuickStart.pdf	13 pp
Read up on one topic	The chapter pages in the sidebar - one page per document	1-18 pp each
Look something up	LCM_Nav3D_Manual.pdf - everything, bookmarked and searchable	127 pp

Every page on this site and every PDF is generated from the same source, so they cannot disagree with each other.

The editor tools, at a glance

Everything below lives behind the Nav3D button in the Level Editor toolbar. If you are looking for a specific panel, this is the fastest way to find which document covers it.

Panel	What it is for	Documented in
Setup Wizard	Configure a level from nothing, in one page	Editor Tools
Health Check	Anything that would stop agents moving, with a Fix button per row	Editor Tools
Auto-Tuner	Measure candidate voxel settings against your real routes and rank them	Editor Tools
Manager panel	Every navigation setting, plus what those settings resolve to	Settings Reference

Building an agent

Approach	Best for	Tutorial
Behavior Tree	Most projects. The familiar route.	03: Your First Flying Agent
StateTree	State-driven behaviour, data binding instead of a blackboard	04: The Same Agent in StateTree
Mass Entity	10,000+ agents through the ECS	06: Mass Entity Crowds
Tactical EQS	Queries that score real volume, not a floor plane	07: Tactical EQS in True 3D

Part I: Getting Started

#	Document	What it covers
01	Installation	Getting the plugin into your project and proving the install is good
02	Core Concepts	What the navigation manager does, and the settings that decide whether it works well
03	Your First Flying Agent	A pawn that flies through 3D space to a goal, in your own level
04	The Same Agent in StateTree	The StateTree route to identical flight behaviour
05	Dynamic Obstacles	Making the world move underneath your agents

Part II: Going Further

#	Document	What it covers
06	Mass Entity Crowds	10,000+ agents pathfound through the Mass ECS
07	Tactical EQS in True 3D	Environment queries that score real volume, not a floor plane
08	AI Perception	Stock UE perception wired into volumetric threat tracking and cover
09	Hybrid Recast + LCM Nav3D	Walking agents on Recast and flying agents on the SVO, in one level
10	Nav Links and Area Modifiers	Traversal shortcuts, and regions agents should avoid or prefer
11	The Gameplay Debugger	Reading agent and plugin state live in PIE

Chapter 12: Behaviour Tree stock patterns

Seven jobs the engine already does well, and where an LCM Nav3D node earns its place instead:

#	Document
1	Wait
2	IsAtLocation
3	LookAt
4	TurnInPlace
5	HealthBelow
6	PerceptionRelay
7	MemoryDecay

Part III: Reference

#	Document	What it covers
13	Settings Reference	Every field on the navigation manager, with verified defaults and limits
14	Troubleshooting	Problems in the order people actually hit them
15	Flight and Swim Locomotion	The 6-DOF dynamics layer that turns guidance into believable movement
16	Mass Trait Reference	Every Mass Entity trait, and the one rule you must not break

Part IV: Appendix

#	Document	What it covers
17	API Reference	Everything you can reach from Blueprint, the Details panel, a Behaviour Tree, a StateTree or a Mass config

Demo maps

The worked examples referred to throughout live in the plugin's Content/Demo/ folder, grouped by Behaviour Tree, StateTree and Mass Entity. Content/Demo/MainMenu is a gallery that opens any of them. Enable Show Plugin Content in the Content Browser to see them.