diff --git a/panda/src/gobj/geom.I b/panda/src/gobj/geom.I
index 3fa32ade36..fb7e858d84 100644
--- a/panda/src/gobj/geom.I
+++ b/panda/src/gobj/geom.I
@@ -379,6 +379,7 @@ calc_tight_bounds(LPoint3 &min_point, LPoint3 &max_point,
  */
 INLINE void Geom::
 mark_internal_bounds_stale(CData *cdata) {
+  cdata->_nested_vertices_stale = true;
   cdata->_internal_bounds_stale = true;
 }
 
@@ -512,6 +513,7 @@ CData() :
   _shade_model(SM_uniform),
   _geom_rendering(0),
   _nested_vertices(0),
+  _nested_vertices_stale(true),
   _internal_bounds_stale(true),
   _bounds_type(BoundingVolume::BT_default)
 {
@@ -527,6 +529,7 @@ CData(GeomVertexData *data) :
   _shade_model(SM_uniform),
   _geom_rendering(0),
   _nested_vertices(0),
+  _nested_vertices_stale(true),
   _internal_bounds_stale(true),
   _bounds_type(BoundingVolume::BT_default)
 {
diff --git a/panda/src/gobj/geom.cxx b/panda/src/gobj/geom.cxx
index 5733c4bee0..624216d38c 100644
--- a/panda/src/gobj/geom.cxx
+++ b/panda/src/gobj/geom.cxx
@@ -1098,9 +1098,9 @@ get_bounds(Thread *current_thread) const {
 int Geom::
 get_nested_vertices(Thread *current_thread) const {
   CDLockedReader cdata(_cycler, current_thread);
-  if (cdata->_internal_bounds_stale) {
+  if (cdata->_nested_vertices_stale) {
     CDWriter cdataw(((Geom *)this)->_cycler, cdata, false);
-    compute_internal_bounds(cdataw, current_thread);
+    compute_nested_vertices(cdataw, current_thread);
     return cdataw->_nested_vertices;
   }
   return cdata->_nested_vertices;
@@ -1468,9 +1468,26 @@ compute_internal_bounds(Geom::CData *cdata, Thread *current_thread) const {
       cdata->_internal_bounds = new BoundingBox;
     }
   }
+  cdata->_internal_bounds_stale = false;
+}
+
+/**
+ * Recomputes the number of nested vertices in this Geom.
+ */
+void Geom::
+compute_nested_vertices(Geom::CData *cdata, Thread *current_thread) const {
+  int num_vertices = 0;
+
+  Primitives::const_iterator pi;
+  for (pi = cdata->_primitives.begin();
+       pi != cdata->_primitives.end();
+       ++pi) {
+    GeomPrimitivePipelineReader reader((*pi).get_read_pointer(current_thread), current_thread);
+    num_vertices += reader.get_num_vertices();
+  }
 
   cdata->_nested_vertices = num_vertices;
-  cdata->_internal_bounds_stale = false;
+  cdata->_nested_vertices_stale = false;
 }
 
 /**
diff --git a/panda/src/gobj/geom.h b/panda/src/gobj/geom.h
index 073805e7ca..986ca5a827 100644
--- a/panda/src/gobj/geom.h
+++ b/panda/src/gobj/geom.h
@@ -185,6 +185,7 @@ private:
 
   INLINE void mark_internal_bounds_stale(CData *cdata);
   void compute_internal_bounds(CData *cdata, Thread *current_thread) const;
+  void compute_nested_vertices(CData *cdata, Thread *current_thread) const;
 
   void do_calc_tight_bounds(LPoint3 &min_point, LPoint3 &max_point,
                             PN_stdfloat &sq_center_dist, bool &found_any,
@@ -327,6 +328,7 @@ private:
 
     CPT(BoundingVolume) _internal_bounds;
     int _nested_vertices;
+    bool _nested_vertices_stale;
     bool _internal_bounds_stale;
     BoundingVolume::BoundsType _bounds_type;
     CPT(BoundingVolume) _user_bounds;