RuntimeMeshPaintTargetComponent

RuntimeMeshPaintTargetComponent is the component that makes an actor paintable.

Add it to the actor that owns the mesh you want to paint. At runtime, the component creates the paint render targets, binds them to the mesh material, resolves paint hits, and applies paint through the GPU painting path.

What It Does

The paint target component is responsible for the mesh-side part of the system:

• Finds the mesh component that should receive paint.
• Creates the runtime color render target.
• Optionally creates the material settings render target.
• Creates the brush preview mask render target.
• Assigns those render targets to dynamic material instances.
• Resolves hit data into UV and surface data.
• Applies paint commands locally.
• Stores replicated paint command history when multiplayer paint replication is enabled.

Required Setup

For a basic paintable mesh, you usually only need:

• A mesh actor in the level.
• RuntimeMeshPaintTargetComponent on that actor.
• A material using the Mesh Painting material function.
• Collision that blocks the painting trace channel, usually Visibility.

The default render target settings are enough for a first test.

Runtime Target Settings

The Runtime Target section controls the render targets and material texture bindings used by the component.

Setting	Purpose
Mesh Targets	Optional list of named mesh components that can be painted.
Create Painted Material Settings Render Target	Creates the extra render target used for painted metallic and roughness data.
Runtime Render Target Width	Width of the runtime paint texture.
Runtime Render Target Height	Height of the runtime paint texture.
Runtime Render Target Format	Texture format used by the runtime render targets.
Initial Paint Color	Starting clear color for the color paint target.
Initial Material Settings Color	Starting clear color for the material settings target.
Painted Color Texture Parameter Name	Material texture parameter that receives the color paint target.
Painted Material Settings Texture Parameter Name	Material texture parameter that receives the material settings target.
Brush Preview Mask Texture Parameter Name	Material texture parameter that receives the GPU brush preview mask.

In most cases, keep the texture parameter names at their defaults and set up the material through the plugin's Mesh Painting material function.

The default parameter names expected by the plugin material function are:

Parameter	Purpose
PaintedColorTexture	Runtime base color paint texture.
PaintedMaterialSettingsTexture	Runtime metallic/roughness paint texture.
BrushPreviewMaskTexture	Runtime brush preview ring mask.

Mesh Targets

If the actor has a single mesh component, the paint target can resolve it automatically.

If the actor has multiple mesh components, use Mesh Targets to choose exactly which components should receive paint. The values are component names, such as StaticMeshComponent0.

If the list contains multiple valid meshes, the component creates runtime paint data for each selected mesh.

UV Channel

UVChannel decides which UV channel is used for hit UV calculation and GPU paint projection.

This must match the UV Index used by the Mesh Painting material function. If these values do not match, paint can appear offset, stretched, or on the wrong part of the mesh.

Max Skeletal Mesh UV Fallback Distance

Max Skeletal Mesh UVFallback Distance is only used by skeletal mesh UV fallback resolution.

• 0.0 disables the distance limit.
• A value greater than 0.0 rejects fallback results if the resolved triangle is farther than that distance from the hit point.

This does not control brush size or preview size.

The current GPU projected painting path avoids using skeletal fallback during the normal brush hot path. Keep this setting at its default unless you are calling lower-level hit resolving functions that explicitly need fallback behavior.

UV Island Clip

Clip Brush to UVIsland keeps large brushes from painting unrelated UV islands when the brush overlaps seams in UV space.

Keep it enabled for most meshes, especially:

• Characters with many UV islands.
• Cubes or hard-surface meshes with separated UV faces.
• Large brush sizes.
• Visible seam areas.

UVIsland Connection Tolerance controls how close UV edges need to be before they are treated as connected. The default is usually correct; only change it if your mesh has unusual UV precision issues.

Replication Settings

The replication settings are used when the paint target should work in multiplayer.

Setting	Purpose
Replicate Runtime Paint	Enables replicated paint commands for this target.
Auto Enable Owner Replication	Lets the component enable replication on the owner actor on authority.
Max Replicated Paint Commands	Limits stored paint history. 0 keeps full history for late join.
Replicated Paint Replay Commands Per Tick	Controls how many stored commands are replayed each tick on clients.
Max Replicated Paint Distance	Optional server validation distance. 0 disables this limit.
Max Replicated Brush Size	Maximum brush size accepted by the server.

For more details, see Multiplayer.

Events

The component exposes paint-specific Blueprint events in the Runtime Mesh Painting | Events category. Unreal also shows the standard Actor Component activation events in the same Details panel.

Event	When It Fires	Typical Use
OnBrushSettingsApplied	After ApplyBrushMaterialSettings stores and clamps the new brush material settings on this target.	React when another system applies color, opacity, metallic, roughness, or erase settings directly to the target.
OnPaintApplied	After a paint command is successfully applied to this target. This also fires when replicated paint commands are replayed locally.	Mark the mesh as dirty, update save state, trigger small effects, or refresh UI that depends on the latest painted result.
OnComponentActivated	Inherited Unreal component event fired when the component is activated.	Use only for normal component activation logic, not for detecting a paint stroke.
OnComponentDeactivated	Inherited Unreal component event fired when the component is deactivated.	Use only for normal component deactivation logic, not for paint completion.

Use OnPaintApplied when you need to know that actual painting happened. Changing brush color or settings by itself should not be treated as a paint event.

Useful Blueprint Functions

Function	Use
InitializeRuntimePaintTarget	Creates runtime render targets and applies them to target materials. Usually called automatically at runtime.
SetTargetMesh	Sets a single mesh component as the paint target.
SetMeshTargets	Sets multiple mesh components as paint targets.
AddMeshTarget	Adds one mesh component to the target list.
ClearMeshTargets	Clears the configured mesh target list.
PaintAtHitWithSettings	Applies paint from an existing hit result and brush settings.
PaintUnderCursorWithSettings	Finds a paint hit under the cursor and applies paint.
SamplePaintedSurfaceColor	Samples the painted color under a hit result for color picking.

Common Mistakes

• The actor has multiple mesh components but Mesh Targets is empty or points to the wrong component name.
• The material does not use the Mesh Painting material function.
• The material UV Index does not match UVChannel.
• The mesh does not block the painting trace channel.
• Clip Brush to UVIsland is disabled and large brushes paint across unrelated UV islands.
• Multiplayer is expected to work, but the target actor or runtime paint replication is disabled.