Tutorial 01: Installation

TL;DR: Put the plugin in YourProject/Plugins/LCMNav3D/, open the project and let it compile, enable Show Plugin Content in the Content Browser, then open a demo map and press Play. If the demo map works, your install is good.

Time: ~10 minutes (plus one compile).

Before you start

The plugin ships as source, so something has to compile it once. Which "something" depends on how you install it.

Method A: Installed from Fab / Epic Games Launcher

This is the simplest path and works with Blueprint-only projects.

1. Install the plugin from the Launcher's Library → Fab Library section. It lands in <Engine>/Plugins/Marketplace/LCMNav3D/ and is already compiled for that engine version.
2. Open your project.
3. Edit → Plugins, search "LCM Nav3D", tick Enabled if it isn't already.
4. Restart the editor when prompted.

Skip to Verify the install.

Method B: Manual install into your project

Use this when you have the plugin as a folder (for example from a direct purchase or a version you re-targeted yourself).

1. Close the editor.

2. Copy the LCMNav3D folder into your project so the layout is:

   YourProject/
     YourProject.uproject
     Plugins/
       LCMNav3D/
         LCMNav3D.uplugin
         Source/
         Content/
         Config/
         Shaders/

Create the Plugins folder if your project doesn't have one. The folder must be named exactly LCMNav3D, because the content mount /LCMNav3D/ depends on it.

3. If your project is Blueprint-only, convert it to C++ first. A Blueprint-only project has no build pipeline and cannot compile a source plugin. The easiest conversion: Tools → New C++ Class → None → Create Class. The editor generates a Source/ folder and restarts. You never have to write any C++ afterwards.

4. Right-click YourProject.uproject → Generate Visual Studio project files.

5. Open the generated .sln and build Development Editor | Win64, or open the .uproject and click Yes when the editor offers to rebuild.

6. The plugin is EnabledByDefault, so it turns itself on. Confirm under Edit → Plugins.

Verify the install

Do all three of these. Each one catches a different kind of failure.

1. The plugin loaded

Edit → Plugins → AI Navigation category. You should see LCM Nav3D, enabled, version 2.2.0.

2. You can see the plugin's content

Plugin content is hidden by default in the Content Browser:

Content Browser → Settings (the gear icon) → tick "Show Plugin Content".

A LCM Nav3D Content folder appears in the tree. Without this you will not find any demo map, and it is by far the most common "the plugin didn't install" false alarm.

3. A demo map actually runs

Open LCM Nav3D Content → Demo → BehaviourTree → InfniteMaps → Vertical_Skyscraper_BT and press Play.

You should see agents flying through the building: over floors, through gaps, not along the ground. Give it a second or two on first play: the navigation volume builds at BeginPlay.

Demo → MainMenu is a gallery of every demo in the plugin, if you would rather browse than open maps by name.

If that works, your install is correct and you can move on to Tutorial 02: Core Concepts.

The engine plugins it turns on

LCMNav3D.uplugin declares these as dependencies, so the engine enables them for you. You do not need to touch them, but it is worth knowing they are on:

If the plugin fails to load with GetLastError 126, one of the Mass plugins got disabled. MassGameplay in particular is required at runtime. Re-enable it and restart.

Common install problems

"The following modules are missing or built with a different engine version: LCMNav3D" The plugin hasn't been compiled for your engine build. Click Yes to rebuild. If the rebuild fails, you are on a Blueprint-only project, so go back to Method B step 3.

I can't find the demo maps. You haven't enabled Show Plugin Content. See verification step 2.

The plugin is missing from the Plugins window entirely. The folder is in the wrong place or misnamed. It must be YourProject/Plugins/LCMNav3D/LCMNav3D.uplugin. Check you didn't end up with a doubled folder like Plugins/LCMNav3D/LCMNav3D/.

Compile errors mentioning StateTree or Mass types. An engine plugin dependency was disabled. Re-enable the table above and regenerate project files.

More in Troubleshooting.

Other engine versions

The plugin ships as a separate copy for each supported engine version, 5.2 through 5.8, and each one is built and verified against that engine.

Install the copy that matches your project rather than re-targeting this one. Engine APIs move between versions, and the per-version copies already carry those differences.

Next: Tutorial 02: Core Concepts. What the navigation manager is actually doing, and the three settings that decide whether it works well in your level.