Footprints + Trails

RT-based ground deformation with two modes: event-triggered footprint stamps and continuous movement-based drag trails.

How It Works

UAgenticFoleyComponent
├── bEnableFootprints → FootprintBrush (event-driven stamps)
│     bDrawOnMovement=false, bDrawEveryFrame=false
│     StampTexture = boot sole mask
│
└── bEnableTrails → TrailBrush (movement-driven)
      bDrawOnMovement=true, bUseMultiDraw=true
      StampTexture = circular blob

Both brushes register with UAgenticFootprintSubsystem (a UWorldSubsystem). The subsystem ticks, allocates brushes to AAgenticDrawingBoard actors placed in the level, and dispatches drawing.

Setup

Enable Footprints

On the foley component:

Enable Trails

Add a Brush Sibling (Advanced)

The foley component auto-creates a default brush if your pawn has none. For per-pawn customization — cull radius, movement tolerance, canvas class filter, explicit mirror flip — add an AgenticInteractBrush sibling component on the character directly:

The default details look like this once added:

Place a DrawingBoard

1. Place an AAgenticDrawingBoard actor in your level
2. Set RTBrushDrawOn to a render target (e.g., RT_Mud)
3. Set CanvasWorldSize to cover your playable area
4. Your ground material reads the RT for displacement

Per-Foot Textures

The FootprintConfigs array on the component supports per-foot texture overrides:

FootprintConfigs = [
  { FootSocket: "foot_l", StampTexture: LeftBootTex, bMirrorFlip: true },
  { FootSocket: "foot_r", StampTexture: RightBootTex, bMirrorFlip: false }
]

3-Layer Fallback

1. Layer 1 — Look up FootSocket name in FootprintConfigs. If matched, use that entry's texture + mirror flip.
2. Layer 2 — No match. Derive mirror flip from socket suffix (_l = true, _r = false) using component's FootprintTexture.
3. Layer 3 — Legacy BP path. Toggles bFootprintMirrorFlip boolean.

Supports asymmetric boots, quadrupeds, left-foot-only textures, and exotic rigs. FootprintConfigs is optional — leave empty for standard UE mannequin.

Shipped Assets

• 3 stamp textures (boot soles)
• 3 render targets
• 5+ blend materials
• MPC_InteractWorld material parameter collection
• MF_MudInteract material function