checkpoint(render): preserve pre-overhaul investigation state

src/AcDream.Content/MeshExtractor.cs

@@ -619,7 +619,22 @@ public sealed class MeshExtractor {
             BoundingBox = boundingBox,
             SortCenter = gfxObj?.SortCenter ?? Vector3.Zero,
             DIDDegrade = gfxObj != null && gfxObj.Flags.HasFlag(GfxObjFlags.HasDIDDegrade) ? gfxObj.DIDDegrade : 0,
-            SelectionSphere = new Sphere { Origin = boundingBox.Center, Radius = Vector3.Distance(boundingBox.Max, boundingBox.Min) / 2.0f }
+            // Retail CGfxObj::Serialize @ 0x00534970 stores drawing_sphere as
+            // BSPTREE::GetSphere(drawing_bsp), and RenderDeviceD3D::DrawMesh
+            // @ 0x005A0860 passes that exact sphere to viewconeCheck.  The
+            // vertex-AABB sphere used here previously is a different shape
+            // (notably on long Facility Hub stair sections) and can change a
+            // portal-edge admission decision.  Preserve the authored root
+            // sphere in prepared content; retain the AABB only for malformed
+            // or drawing-BSP-less assets which have no retail sphere to carry.
+            SelectionSphere = gfxObj?.DrawingBSP?.Root?.BoundingSphere
+                ?? new Sphere
+                {
+                    Origin = boundingBox.Center,
+                    Radius = Vector3.Distance(
+                        boundingBox.Max,
+                        boundingBox.Min) / 2.0f,
+                }
         };
     }
 

src/AcDream.Content/Pak/PakFormat.cs

@@ -31,9 +31,13 @@ public static class PakFormat {
     /// binary format remains version 1. Version 6 introduces pak format 2:
     /// globally shared texture payloads plus independently Brotli-compressed
     /// blobs with raw fallback. Mesh geometry and source texture bytes remain
-    /// exact; unedited DXT surfaces now retain their native BC blocks.
+    /// exact; unedited DXT surfaces now retain their native BC blocks. Version
+    /// 7 replaces the synthetic vertex-AABB GfxObj view sphere with retail's
+    /// authored DrawingBSP root sphere. The binary format remains version 2,
+    /// but every prepared GfxObj render record must be regenerated because
+    /// the sphere participates in portal-view admission.
     /// </summary>
-    public const uint CurrentBakeToolVersion = 6;
+    public const uint CurrentBakeToolVersion = 7;
 }
 
 /// <summary>