diff --git a/src/AcDream.App/Rendering/IndoorCellStencilPipeline.cs b/src/AcDream.App/Rendering/IndoorCellStencilPipeline.cs
index f13dda5..4ee53e1 100644
--- a/src/AcDream.App/Rendering/IndoorCellStencilPipeline.cs
+++ b/src/AcDream.App/Rendering/IndoorCellStencilPipeline.cs
@@ -264,6 +264,80 @@ public sealed unsafe class IndoorCellStencilPipeline : IDisposable
         _gl.Disable(EnableCap.StencilTest);
     }
 
+    /// <summary>
+    /// Phase A8.F: mark a pre-projected NDC clip region into stencil bit 1 and far-depth-punch it.
+    /// Replaces the flat world-space exit-portal path (PortalMeshBuilder.BuildTriangles) with the
+    /// recursively-clipped region from PortalVisibilityBuilder.OutsideView. Polygons are triangulated
+    /// (fan) and uploaded as NDC verts (z=0) drawn with an identity view-projection (already clip-space).
+    /// GL state on exit matches MarkAndPunch: stencil disabled, color+depth on, depth=Less.
+    /// </summary>
+    public void MarkAndPunchNdc(System.Collections.Generic.IReadOnlyList<ViewPolygon> region)
+    {
+        // Triangulate the region (fan per convex polygon) into NDC Vector3 (z=0).
+        int triVerts = 0;
+        foreach (var p in region) if (!p.IsEmpty) triVerts += (p.Vertices.Length - 2) * 3;
+        if (triVerts == 0) { _lastVertexCount = 0; return; }
+
+        var verts = new Vector3[triVerts];
+        int idx = 0;
+        foreach (var p in region)
+        {
+            if (p.IsEmpty) continue;
+            var v0 = new Vector3(p.Vertices[0], 0f);
+            for (int i = 1; i < p.Vertices.Length - 1; i++)
+            {
+                verts[idx++] = v0;
+                verts[idx++] = new Vector3(p.Vertices[i], 0f);
+                verts[idx++] = new Vector3(p.Vertices[i + 1], 0f);
+            }
+        }
+
+        if (triVerts > _vboCapacityVerts) AllocateVbo(Math.Max(triVerts * 2, 1024));
+        _gl.BindBuffer(BufferTargetARB.ArrayBuffer, _vbo);
+        fixed (Vector3* p = verts)
+            _gl.BufferSubData(BufferTargetARB.ArrayBuffer, 0, (nuint)(triVerts * sizeof(Vector3)), p);
+        _gl.BindBuffer(BufferTargetARB.ArrayBuffer, 0);
+        _lastVertexCount = triVerts;
+
+        // Same GL state machine as MarkAndPunch, but identity VP (verts are already NDC).
+        var identity = Matrix4x4.Identity;
+
+        _gl.Enable(EnableCap.StencilTest);
+        _gl.Enable(EnableCap.DepthTest);
+        _gl.ClearStencil(0);
+        _gl.Clear(ClearBufferMask.StencilBufferBit);
+
+        // Step 1: mark bit 1.
+        _gl.ColorMask(false, false, false, false);
+        _gl.DepthMask(false);
+        _gl.DepthFunc(DepthFunction.Always);
+        _gl.Disable(EnableCap.CullFace);
+        _gl.StencilFunc(StencilFunction.Always, 1, 0xFFu);
+        _gl.StencilMask(0x01u);
+        _gl.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Replace);
+        _shader.Use();
+        _gl.UniformMatrix4(_uViewProjectionLoc, 1, false, (float*)&identity);
+        _gl.Uniform1(_uWriteFarDepthLoc, 0);
+        _gl.BindVertexArray(_vao);
+        _gl.DrawArrays(PrimitiveType.Triangles, 0, (uint)triVerts);
+
+        // Step 2: far-depth punch where bit 1 is set.
+        _gl.DepthMask(true);
+        _gl.DepthFunc(DepthFunction.Always);
+        _gl.StencilFunc(StencilFunction.Equal, 1, 0x01u);
+        _gl.StencilMask(0x00u);
+        _gl.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Keep);
+        _gl.Uniform1(_uWriteFarDepthLoc, 1);
+        _gl.DrawArrays(PrimitiveType.Triangles, 0, (uint)triVerts);
+        _gl.BindVertexArray(0);
+
+        // Clean state for the indoor-entities pass (matches MarkAndPunch exit).
+        _gl.Enable(EnableCap.CullFace);
+        _gl.ColorMask(true, true, true, true);
+        _gl.DepthFunc(DepthFunction.Less);
+        _gl.Disable(EnableCap.StencilTest);
+    }
+
     /// <summary>
     /// Step 4 of WB's RenderInsideOut: enable stencil read-only with
     /// ref=1, so subsequent terrain + outdoor entity draws are gated