diff --git a/src/runtime-three/runtime-host.ts b/src/runtime-three/runtime-host.ts
index 80da7830..0a56eb30 100644
--- a/src/runtime-three/runtime-host.ts
+++ b/src/runtime-three/runtime-host.ts
@@ -51,6 +51,7 @@ import {
   type Brush,
   type WhiteboxFaceId
 } from "../document/brushes";
+import { createEmptyTerrainFoliageBlockerMask } from "../document/terrains";
 import {
   mapWorldPointToScenePathProgressBetweenPoints,
   resolveNearestPointOnResolvedScenePath,