diff --git a/src/viewport-three/viewport-host.ts b/src/viewport-three/viewport-host.ts
index c46d3ef9..baa7c13c 100644
--- a/src/viewport-three/viewport-host.ts
+++ b/src/viewport-three/viewport-host.ts
@@ -1204,6 +1204,10 @@ export class ViewportHost {
     this.boxCreatePreviewMesh.material.dispose();
     this.boxCreatePreviewEdges.geometry.dispose();
     this.boxCreatePreviewEdges.material.dispose();
+    this.terrainBrushPreviewLine.geometry.dispose();
+    this.terrainBrushPreviewLine.material.dispose();
+    this.terrainBrushPreviewCenter.geometry.dispose();
+    this.terrainBrushPreviewCenter.material.dispose();
     this.renderer.forceContextLoss();
     this.renderer.dispose();