diff --git a/packages/core/src/hooks/spatial-grid/spatial-grid-manager.ts b/packages/core/src/hooks/spatial-grid/spatial-grid-manager.ts
index f58893f6..8138efe9 100644
--- a/packages/core/src/hooks/spatial-grid/spatial-grid-manager.ts
+++ b/packages/core/src/hooks/spatial-grid/spatial-grid-manager.ts
@@ -468,7 +468,8 @@ export class SpatialGridManager {
       if (slab.polygon.length >= 3 && pointInPolygon(x, z, slab.polygon)) {
         // Check if point is in any hole
         let inHole = false
-        for (const hole of slab.holes) {
+        const holes = slab.holes || []
+        for (const hole of holes) {
           if (hole.length >= 3 && pointInPolygon(x, z, hole)) {
             inHole = true
             break
@@ -507,7 +508,8 @@ export class SpatialGridManager {
         // We consider it entirely in a hole if the item center is in the hole
         let inHole = false
         const [cx, , cz] = position
-        for (const hole of slab.holes) {
+        const holes = slab.holes || []
+        for (const hole of holes) {
           if (hole.length >= 3 && pointInPolygon(cx, cz, hole)) {
             inHole = true
             break
@@ -546,7 +548,8 @@ export class SpatialGridManager {
         let inHole = false
         const midX = (start[0] + end[0]) / 2
         const midZ = (start[1] + end[1]) / 2
-        for (const hole of slab.holes) {
+        const holes = slab.holes || []
+        for (const hole of holes) {
           if (hole.length >= 3 && pointInPolygon(midX, midZ, hole)) {
             inHole = true
             break
diff --git a/packages/core/src/systems/slab/slab-system.tsx b/packages/core/src/systems/slab/slab-system.tsx
index 945e80c3..29a2c8b6 100644
--- a/packages/core/src/systems/slab/slab-system.tsx
+++ b/packages/core/src/systems/slab/slab-system.tsx
@@ -124,7 +124,8 @@ export function generateSlabGeometry(slabNode: SlabNode): THREE.BufferGeometry {
   shape.closePath()
 
   // Add holes to the shape
-  for (const holePolygon of slabNode.holes) {
+  const holes = slabNode.holes || []
+  for (const holePolygon of holes) {
     if (holePolygon.length < 3) continue
 
     const holePath = new THREE.Path()