diff --git a/src/AcDream.App/Rendering/GameWindow.cs b/src/AcDream.App/Rendering/GameWindow.cs
index 73ccb1c..2b9bfb0 100644
--- a/src/AcDream.App/Rendering/GameWindow.cs
+++ b/src/AcDream.App/Rendering/GameWindow.cs
@@ -4284,6 +4284,36 @@ public sealed class GameWindow : IDisposable
                 }
             }
 
+            // L-fix3 (2026-04-28): retail "decorative / phantom" detection.
+            // A Setup is phantom (no collision) when it has NO CylSpheres,
+            // NO Spheres, AND zero overall Radius. Small plants, grass
+            // tufts, flowers, ground-cover bushes all match — retail
+            // ships them with empty collision arrays so the player walks
+            // through them. Without this gate the mesh-bounds fallback
+            // below assigns every plant a 0.3 m+ collision cylinder
+            // (line ~4409 clamp) and they block the player.
+            //
+            // The gate is layered AFTER the Setup CylSphere / BSP
+            // registrations above (which are no-ops for phantom Setups
+            // anyway), so non-phantom scenery (trees with real
+            // CylSpheres or canopy-only BSPs) still gets the
+            // mesh-bounds fallback. The check is on entity.SourceGfxObjOrSetupId
+            // to look up the cached Setup; if it's a raw GfxObj
+            // (0x010xxxxx, no Setup metadata) we keep the old fallback
+            // behaviour because GfxObjs don't expose phantom intent.
+            bool isPhantomSetup = false;
+            if ((entity.SourceGfxObjOrSetupId & 0xFF000000u) == 0x02000000u)
+            {
+                var setupInfoForPhantom = _physicsDataCache.GetSetup(entity.SourceGfxObjOrSetupId);
+                if (setupInfoForPhantom is not null
+                    && setupInfoForPhantom.CylSpheres.Count == 0
+                    && setupInfoForPhantom.Spheres.Count == 0
+                    && setupInfoForPhantom.Radius <= 0.0001f)
+                {
+                    isPhantomSetup = true;
+                }
+            }
+
             // VISUAL mesh-bounds collision: for SCENERY entities (IDs with
             // 0x80000000 bit set, indicating procedurally-placed scenery),
             // ALWAYS compute a cylinder from the world-space mesh AABB.
@@ -4294,7 +4324,12 @@ public sealed class GameWindow : IDisposable
             // For stabs (low IDs) and live entities, keep the existing Setup
             // CylSphere / BSP registrations — those are placed with precise
             // frame data and don't have the scenery offset issue.
-            if ((_isOutdoorMesh || (entityBsp == 0 && entityCyl == 0)) && entity.MeshRefs.Count > 0)
+            //
+            // L-fix3: skip entirely when the Setup is phantom — retail
+            // decorative meshes have no collision data on purpose.
+            if (!isPhantomSetup
+                && (_isOutdoorMesh || (entityBsp == 0 && entityCyl == 0))
+                && entity.MeshRefs.Count > 0)
             {
                 float entScale = entity.Scale > 0f ? entity.Scale : 1f;
                 bool haveBounds = false;