diff --git a/src/mesh/model.js b/src/mesh/model.js
index f0229544..3d5f0f04 100644
--- a/src/mesh/model.js
+++ b/src/mesh/model.js
@@ -149,8 +149,9 @@ mesh.model = class MeshModel extends mesh.object {
         let geo = this.mesh.geometry;
         geo.setAttribute('position', new BufferAttribute(vertices, 3));
         geo.setAttribute('normal', undefined);
+        // signal util.box3expand that geometry changed
+        geo._model_invalid = true;
         if (indices) geo.setIndex(new BufferAttribute(indices, 1));
-        geo.attributes.position.needsUpdate = true;
         if (!normals) geo.computeVertexNormals();
         // persist in db so it can be restored on page load
         mapp.db.space.put(this.id, { file: this.file, mesh: vertices });
diff --git a/src/mesh/util.js b/src/mesh/util.js
index 8172e929..98db5a4c 100644
--- a/src/mesh/util.js
+++ b/src/mesh/util.js
@@ -110,7 +110,8 @@ let util = mesh.util = {
             let matrix = object.matrixWorld;
             let bkey = [matrix.elements.map(v => v.round(5))].join(',')
             let cached = boundsCache[object.id];
-            if (!cached || cached.bkey !== bkey) {
+            // geometry._model_invalid set on model.reload(), usually after a split
+            if (!cached || cached.bkey !== bkey || geometry._model_invalid) {
                 let position = geometry.attributes.position.clone();
                 position.applyMatrix4(new Matrix4().extractRotation(matrix));
                 let bounds = new Box3().setFromBufferAttribute(position);
@@ -118,6 +119,7 @@ let util = mesh.util = {
                 // bounds.min.multiply(scale);
                 // bounds.max.multiply(scale);
                 cached = boundsCache[object.id] = { bkey, bounds };
+                geometry._model_invalid = undefined;
             }
             let bt = cached.bounds.clone();
             let m4 = new Matrix4();