diff --git a/src/AcDream.Core/World/SceneryGenerator.cs b/src/AcDream.Core/World/SceneryGenerator.cs
index 610d4fe..d4ae229 100644
--- a/src/AcDream.Core/World/SceneryGenerator.cs
+++ b/src/AcDream.Core/World/SceneryGenerator.cs
@@ -59,6 +59,7 @@ public static class SceneryGenerator
         float[]? heightTable = null)
     {
         var result = new List<ScenerySpawn>();
+        var sortingRadiusCache = new Dictionary<uint, float>();
 
         if (region.TerrainInfo?.TerrainTypes is null || region.SceneInfo?.SceneTypes is null)
             return result;
@@ -182,6 +183,15 @@ public static class SceneryGenerator
                         if (nz < obj.MinSlope || nz > obj.MaxSlope) continue;
                     }
 
+                    // Retail obj_within_block check: the model's sorting sphere must
+                    // fit entirely within the landblock bounds. This rejects edge-vertex
+                    // spawns whose bounding sphere would extend past the boundary.
+                    // Named-retail: CPhysicsObj::obj_within_block (0x00461c30), called
+                    // inside CLandBlock::get_land_scenes after find_terrain_poly/CheckSlope.
+                    float sortRadius = GetSortingSphereRadius(dats, obj.ObjectId, sortingRadiusCache);
+                    if (!IsWithinBlock(lx, ly, sortRadius))
+                        continue;
+
                     // BaseLoc.Z offset: scenery-specific vertical offset from
                     // the ground (e.g., flowers planted at -0.1m so they
                     // don't float above grass). The renderer adds groundZ
@@ -262,20 +272,10 @@ public static class SceneryGenerator
     /// </summary>
     private const float RoadHalfWidth = 5.0f;
 
-    /// <summary>
-    /// Retail-faithful post-displacement road test. Ported from ACViewer
-    /// Landblock.OnRoad (Physics/Common/Landblock.cs lines 300-398), which is
-    /// a direct port of FUN_00530d30 in the retail client.
-    ///
-    /// Examines the 4 corners of the cell containing (lx, ly) and, depending
-    /// on how many are road vertices (0, 1, 2, 3, or 4), applies a polygonal
-    /// test using the 5-unit road half-width to check if (lx, ly) lies on the
-    /// road ribbon. Returns true if the point is on a road.
-    /// </summary>
     /// <summary>
     /// Retail-faithful road ribbon test — direct port of ACViewer's
     /// Landblock.OnRoad (Physics/Common/Landblock.cs lines 300-398), which
-    /// itself is a port of FUN_00530d30 in acclient.exe.
+    /// itself is a port of CLandBlock::on_road (named-retail 0x0052FFF0).
     ///
     /// Classifies the 4 corners of the cell containing (lx, ly) by road type
     /// (bits 0-1 of the terrain word) and applies a different geometric test
@@ -370,6 +370,54 @@ public static class SceneryGenerator
 
     private const int CellsPerSide = 8;
 
+    /// <summary>
+    /// Retail CPhysicsObj::obj_within_block check — verifies the object's sorting
+    /// sphere stays entirely within the landblock bounds. Returns true if the object
+    /// is within bounds.
+    ///
+    /// Named-retail: CPhysicsObj::obj_within_block (0x00461c30).
+    /// ACViewer: PhysicsObj.obj_within_block.
+    ///
+    /// Retail loads the full PhysicsObj, transforms the sorting sphere center via
+    /// LocalToGlobal, then checks center ± radius against [0, BlockLength].
+    /// We approximate by ignoring the sorting sphere center offset (typically small
+    /// for scenery) and checking the spawn position directly against [radius, 192-radius].
+    /// </summary>
+    private static bool IsWithinBlock(float lx, float ly, float sortingSphereRadius)
+    {
+        if (sortingSphereRadius <= 0f) return true;
+        return lx >= sortingSphereRadius && ly >= sortingSphereRadius
+            && lx < LandblockSize - sortingSphereRadius
+            && ly < LandblockSize - sortingSphereRadius;
+    }
+
+    /// <summary>
+    /// Gets the sorting sphere radius for a scenery object, with caching.
+    /// Setup objects (0x02xxxxxx) use Setup.SortingSphere.Radius.
+    /// GfxObj objects (0x01xxxxxx) fall back to 0 (allows placement; these are
+    /// typically small items like grass patches whose BSP sphere is tiny).
+    /// </summary>
+    private static float GetSortingSphereRadius(
+        DatCollection dats, uint objectId, Dictionary<uint, float> cache)
+    {
+        if (cache.TryGetValue(objectId, out float cached))
+            return cached;
+
+        float radius = 0f;
+        if ((objectId >> 24) == 0x02)
+        {
+            // Setup — has an explicit SortingSphere
+            var setup = dats.Get<Setup>(objectId);
+            if (setup?.SortingSphere is { } sphere)
+                radius = sphere.Radius;
+        }
+        // GfxObj (0x01) — no Setup.SortingSphere; use 0 (permissive).
+        // These are typically small single-mesh scenery items.
+
+        cache[objectId] = radius;
+        return radius;
+    }
+
     /// <summary>
     /// Pseudo-random displacement within a cell for a scenery object. Returns a
     /// Vector3 in local cell-offset space (the caller adds it to the cell corner