Create MetaHuman Crowds

This page walks through the end-to-end process of setting up a MetaHuman crowd in a level.

What you need

Setting up a MetaHuman crowd requires the following:

• Prepare source assets - create or import the MetaHuman characters, Groom assets, and clothing you want your crowd to use.

• Create a Collection - create a MetaHuman Collection asset, assign the Crowd Collection Pipeline, and populate it with your source assets.

• Build the Collection - the pipeline processes every item and generates crowd-optimized assets.

• Create Instances - create MetaHuman Instances from the Collection, each with a different combination of character, hair, and clothing. Adjust instance parameters such as skin tone, hair color, and clothing tint to add further variety.

• Create a Mass Entity Config - set up a Mass Entity Config asset that tells the Mass framework what your crowd characters look like and how they should behave.

• Set up the level - place a Mass Spawner actor, assign it the entity config, and configure the spawn area.

After this is in place, your crowd spawns when the level starts. Preview it using Play in Editor.

Create a Collection

1. Right-click in the Content Browser.

2. Select MetaHuman > MetaHuman Collection to create a new MetaHuman Collection asset.

3. Open the Collection.

4. In the Details panel, set the Pipeline to the Crowd Pipeline (BP_CrowdPipeline).

The Crowd Pipeline defines the following slots:

Drag assets from the Content Browser into the Items panel to populate the Collection. The more items you add to each slot, the more variety your crowd can have. For example, you might add four MetaHuman Characters to the Head and Body slots, six hairstyles, and a selection of tops, bottoms, and shoes.

For more information about Collections workflows and settings, see the MetaHuman Collections page.

Build the Collection

After populating the Collection, click Apply in the Collection Editor toolbar to build it. The pipeline processes heads, bodies, outfits, and grooms, and generates optimized assets for each.

Generated assets are stored inside the Collection. See the MetaHuman Collection and Instance Assets documentation for details on managing generated assets.

Build Settings

The pipeline exposes build settings that control the trade-off between visual quality and performance.

Create Instances

1. Right-click the Collection in the Content Browser and select Create New Instance to create a MetaHuman Instance.

   1. Each Instance represents one distinct crowd character appearance.

2. In each Instance, select which MetaHuman Character to use for the head and body, which hairstyle and grooms to use, and which clothing items to wear.

   1. You can also adjust Instance Parameters such as hair color and clothing tint to add variety beyond the slot selections.

Create as many Instances as you need for the level of visual variety you want.

For more information about Instance workflows and settings, see the MetaHuman Instances page.

Set up Mass Entity

The Mass Entity framework handles spawning crowd characters into the level and managing their LOD. Configure it by creating a Mass Entity Config asset that describes what a crowd entity looks like and how it behaves.

Create a Mass Entity Config

1. Right-click in the Content Browser and select Data > Data Asset.

2. In the Data Asset window select Mass Entity Config Asset from the list to create the asset.

3. Open it and add the traits described below.

MetaHuman Crowd Visualization Trait

This is the core trait. It tells the Mass framework what your crowd characters look like. Add a MetaHuman Crowd Visualization trait and configure the following properties:

The trait also exposes LOD behavior settings that control how close a character must be before it renders as a full actor, at what distance characters switch to a lightweight instanced representation, and at what distance they stop rendering entirely. You can also set maximum character counts per LOD level. For example, you might allow 10 full-quality actors at close range but hundreds of instanced characters at a distance.

Animation scalability settings control how much variety there is in the animation timing of distant characters to avoid, visible lockstep in looping crowds, how many characters can smoothly blend between animations at the same time, and how long animation blends take.

Crowd Member Trait

Add a CrowdMember trait to enable crowd navigation. This registers the entity with the Mass Crowd system for movement.

Actor Blueprints

The actor Blueprint referenced by the visualization trait must implement the MetaHuman Character Actor Interface (IMetaHumanCharacterActorInterface) so the system can apply assembled MetaHuman data to it. The sample content provides an example Blueprint you can use directly or as a starting point.

For actors driven by Mass, you can also implement the MetaHuman Mass Crowd Actor Blueprint Interface (IMetahumanMassCrowdActorBlueprintInterface). This interface lets Mass read and write animation state on the actor each tick.

Set up the Level

After you have your Collection, Instances, and Mass Entity Config, you can set up a crowd in a level.

Place a Mass Spawner

1. Place an AMassSpawner actor in the level.

2. In the spawner's Entity Types array, add an entry and set its Entity Config to your Mass Entity Config asset.

3. Set the Count to the number of crowd entities to spawn.

Configure a Spawn Area

The Mass Spawner needs to know where to place entities. Add a Spawn Data Generator to the spawner's Generators array to define the spawn area. For example, use an Environment Query System (EQS)-based generator to distribute spawn locations across an area.

Set up Navigation

If your crowd characters need to move, place a NavMesh Bounds Volume over the area where they should navigate.

Spawn Timing

By default, the Mass Spawner spawns entities on Begin Play. Disable Auto Spawn on Begin Play if you want to trigger spawning from Blueprint or C++ instead.

The Spawning Count Scale property is a multiplier on the spawn count. Use it to adjust crowd density based on platform or quality settings.

Run the Crowd

Press Play in Editor to see your crowd. The Mass Spawner creates entities, the visualization trait assembles their MetaHuman appearances, and the LOD system manages rendering as you move the camera.

• Characters close to the camera render as full MetaHuman actors driven by Anim Blueprints.

• As distance increases, characters transition to lightweight instanced meshes driven by pre-baked GPU animation.

• At very long distances, characters stop rendering entirely.

Optimize MetaHuman Crowds

The following adjustments give you the most control over the balance between visual quality and performance.

Adjust Crowd Density Per Platform

Use the Mass Spawner’s Spawning Count Scale property to scale crowd density per platform. Set this from a scalability CVar or Blueprint logic to reduce crowd size on lower-end hardware. Refer to the platform spawn count limits on the MetaHuman Crowds overview page when setting your baseline counts.

Tune LOD Settings

The LOD settings on the MetaHuman Crowd Visualization trait are the primary performance control for crowd scenes:

• Reducing the distance at which characters switch from full actors to instanced meshes lowers CPU cost.

• Reducing the maximum render distance lowers GPU cost.

• Capping the maximum count at each LOD level prevents the most resource-intensive representations from scaling beyond your performance budget.

For example, you might allow 10 full-quality actors at close range but hundreds of instanced characters at a distance.

Adjust Build Quality for Close-range Crowds

If your crowd will be seen at closer range than usual, use the controls in the Collection's Details panel to increase the quality settings for higher mesh detail. This improves visual quality at the cost of higher memory use.