diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 4fbbf92..db3f64d 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -1,3 +1,7 @@
+### 5.3.0-prerelease012
+- structured point clouds: filtered nodes
+- structured point clouds: chunk TryGetPartIndices
+
 ### 5.3.0-prerelease011
 - updated base packages to 5.2.28
 
diff --git a/src/Aardvark.Data.Points.Base/Chunk.cs b/src/Aardvark.Data.Points.Base/Chunk.cs
index 7fd1e88..5b701f8 100644
--- a/src/Aardvark.Data.Points.Base/Chunk.cs
+++ b/src/Aardvark.Data.Points.Base/Chunk.cs
@@ -95,6 +95,11 @@ public GenericChunk ToGenericChunk()
         [MemberNotNullWhen(true, nameof(PartIndexRange))]
         public bool HasPartIndexRange => PartIndexRange != null;
 
+        public IList<int>? TryGetPartIndices()
+        {
+            return PartIndexUtils.Expand(PartIndices, Count);
+        }
+
         public static Chunk ImmutableMerge(Chunk a, Chunk b)
         {
             if (a is null || a.IsEmpty) return b;
diff --git a/src/Aardvark.Data.Points.Base/PartIndexUtils.cs b/src/Aardvark.Data.Points.Base/PartIndexUtils.cs
index 1d51463..bed8db7 100644
--- a/src/Aardvark.Data.Points.Base/PartIndexUtils.cs
+++ b/src/Aardvark.Data.Points.Base/PartIndexUtils.cs
@@ -63,6 +63,27 @@ public static bool HasValidPartIndexData(IReadOnlyDictionary<Durable.Def, object
         return i == 1; // exactly one of the above must exist
     }
 
+    /// <summary>
+    /// Expands part indices: All input types are expanded into an int array.
+    /// </summary>
+    public static int[]? Expand(object? o, int ct)
+    {
+        switch (o)
+        {
+            case null: return null;
+            case int x: return new int[ct].Set(x);
+            case uint x: checked { return new int[ct].Set((int)x); }
+            case byte[] xs: return xs.Map(x => (int)x);
+            case short[] xs: return xs.Map(x => (int)x);
+            case int[] xs: return xs;
+            default:
+                throw new Exception(
+                $"Unexpected type {o.GetType().FullName}. " +
+                $"Error 278c88f6-d504-4a17-9752-8cca614505f1."
+                );
+        }
+    }
+
     /// <summary>
     /// Compacts part indices.
     /// If per-point indices are all identical, then return per-cell index.
diff --git a/src/Aardvark.Geometry.PointSet/Octrees/PointSetNode.cs b/src/Aardvark.Geometry.PointSet/Octrees/PointSetNode.cs
index d534445..5e5ba2a 100644
--- a/src/Aardvark.Geometry.PointSet/Octrees/PointSetNode.cs
+++ b/src/Aardvark.Geometry.PointSet/Octrees/PointSetNode.cs
@@ -940,19 +940,8 @@ public object? PartIndices
         /// </summary>
         public bool TryGetPartIndices([NotNullWhen(true)] out int[]? result)
         {
-            switch (PartIndices)
-            {
-                case null: result = null; return false;
-                case int x: result = new int[PointCountCell].Set(x); return true;
-                case uint x: checked { result = new int[PointCountCell].Set((int)x); return true; }
-                case byte[] xs: result = xs.Map(x => (int)x); return true;
-                case short[] xs: result = xs.Map(x => (int)x); return true;
-                case int[] xs: result = xs; return true;
-                default: throw new Exception(
-                    $"Unexpected type {PartIndices.GetType().FullName}. " +
-                    $"Error 278c88f6-d504-4a17-9752-8cca614505f1."
-                    );
-            }
+            result = PartIndexUtils.Expand(PartIndices, PointCountCell);
+            return result != null;
         }
 
         #endregion
diff --git a/src/Aardvark.Geometry.PointSet/Views/FilteredNode.cs b/src/Aardvark.Geometry.PointSet/Views/FilteredNode.cs
index e7e78d2..5835a17 100644
--- a/src/Aardvark.Geometry.PointSet/Views/FilteredNode.cs
+++ b/src/Aardvark.Geometry.PointSet/Views/FilteredNode.cs
@@ -12,6 +12,7 @@ You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 using Aardvark.Base;
+using Aardvark.Base.Sorting;
 using Aardvark.Data;
 using Aardvark.Data.Points;
 using System;
@@ -499,7 +500,7 @@ public Range1i? PartIndexRange
         /// <summary>
         /// Octree. Per-point or per-cell part indices.
         /// </summary>
-        public object? PartIndices => PartIndexUtils.Subset(Node.PartIndices, null!);
+        public object? PartIndices => SubsetIndexArray != null ? PartIndexUtils.Subset(Node.PartIndices, SubsetIndexArray) : Node.PartIndices;
 
         /// <summary>
         /// Get per-point part indices as an int array (regardless of internal representation).
@@ -507,7 +508,7 @@ public Range1i? PartIndexRange
         /// </summary>
         public bool TryGetPartIndices([NotNullWhen(true)] out int[]? result)
         {
-            var qs = SubsetIndexArray != null ? PartIndexUtils.Subset(PartIndices, SubsetIndexArray) : PartIndices;
+            var qs = PartIndices;
 
             if (m_cache.TryGetValue(Octree.PerPointPartIndex1i.Id, out var _result))
             {
@@ -635,10 +636,9 @@ private int[]? SubsetIndexArray
                 if (_subsetIndexArray != null) return _subsetIndexArray;
                 if (m_activePoints == null) return null;
 
-                var imax = PointCountCell;
-                var xs = new List<int>();
-                for (var i = 0; i < imax; i++) if (m_activePoints.Contains(i)) xs.Add(i);
-                return _subsetIndexArray = xs.ToArray();
+                var xs = m_activePoints.ToArray();
+                xs.QuickSortAscending();
+                return _subsetIndexArray = xs;
             }
         }