diff --git a/Src/Graphics/Legacy3D/Legacy3D.cpp b/Src/Graphics/Legacy3D/Legacy3D.cpp
index 360b181..efa1b07 100644
--- a/Src/Graphics/Legacy3D/Legacy3D.cpp
+++ b/Src/Graphics/Legacy3D/Legacy3D.cpp
@@ -162,11 +162,6 @@
 #include <cmath>
 #include <cstdint>
 
-#ifdef DEBUG
-extern bool g_forceFlushModels;
-#endif
-
-
 namespace Legacy3D {
 
 // Microsoft doesn't provide isnan() and isinf()
@@ -668,9 +663,13 @@ void CLegacy3D::DescendCullingNode(UINT32 addr)
     m_colorTableAddr &= 0x000FFFFF; // clamp to 4MB (in words) range
   }
 
-//printf("%08x NODE %d\n", addr, stackDepth);
-//for (int i = 0; i < 8; i++)
-//  printf("  %08x\n", node[i]);
+#ifdef DEBUG
+  bool oldDebugHighlightAll = m_debugHighlightAll;
+  m_debugHighlightAll = (m_debugHighlightCullingNodeIdx >= 0) && (node[m_debugHighlightCullingNodeIdx] & m_debugHighlightCullingNodeMask) != 0;
+#endif
+  //printf("%08x NODE %d\n", addr, stackDepth);
+  //for (int i = 0; i < 8; i++)
+  //  printf("  %08x\n", node[i]);
 
   // Debug: texture offset? (NOTE: offsets 1 and 2 don't exist on step 1.0)
   //if (node[0x02]&0xFFFF)
@@ -716,6 +715,9 @@ void CLegacy3D::DescendCullingNode(UINT32 addr)
 
   // Proceed to second link
   glPopMatrix();
+#ifdef DEBUG
+  m_debugHighlightAll = oldDebugHighlightAll;
+#endif
   if ((node[0x00] & 0x07) != 0x06)  // seems to indicate second link is invalid (fixes circular references)
     DescendNodePtr(node2Ptr);
   --stackDepth;
@@ -1001,7 +1003,11 @@ void CLegacy3D::RenderFrame(void)
   
   // Draw
 #ifdef DEBUG
-  if (g_forceFlushModels)
+  m_debugHighlightPolyHeaderIdx = m_config["Debug/HighlightPolyHeaderIdx"].ValueAsDefault<int>(-1);
+  m_debugHighlightPolyHeaderMask = m_config["Debug/HighlightPolyHeaderMask"].ValueAsDefault<uint32_t>(0);
+  m_debugHighlightCullingNodeIdx = m_config["Debug/HighlightCullingNodeIdx"].ValueAsDefault<int>(-1);
+  m_debugHighlightCullingNodeMask = m_config["Debug/HighlightCullingNodeMask"].ValueAsDefault<uint32_t>(0);
+  if (m_config["Debug/ForceFlushModels"].ValueAsDefault<bool>(false))
     ClearModelCache(&VROMCache);
 #endif
   ClearModelCache(&PolyCache);
diff --git a/Src/Graphics/Legacy3D/Legacy3D.h b/Src/Graphics/Legacy3D/Legacy3D.h
index 0e113e1..9185b6c 100644
--- a/Src/Graphics/Legacy3D/Legacy3D.h
+++ b/Src/Graphics/Legacy3D/Legacy3D.h
@@ -390,6 +390,15 @@ private:
   
   const Util::Config::Node &m_config;
 	
+#ifdef DEBUG
+	// Debug
+	int m_debugHighlightPolyHeaderIdx = -1;
+	uint32_t m_debugHighlightPolyHeaderMask = 0;
+	int m_debugHighlightCullingNodeIdx = -1;
+	uint32_t m_debugHighlightCullingNodeMask = 0;
+	bool m_debugHighlightAll = false;
+#endif
+	
 	// Stepping
 	int		step;
 	int		offset;			// offset to subtract for words 3 and higher of culling nodes
diff --git a/Src/Graphics/Legacy3D/Models.cpp b/Src/Graphics/Legacy3D/Models.cpp
index 3d952d2..16521a7 100644
--- a/Src/Graphics/Legacy3D/Models.cpp
+++ b/Src/Graphics/Legacy3D/Models.cpp
@@ -754,9 +754,9 @@ void CLegacy3D::InsertVertex(ModelCache *Cache, const Vertex *V, const Poly *P,
     contourProcessing = 1.0f;
 
 #ifdef DEBUG
-  if (g_testPolyHeaderIdx >= 0)
+  if (m_debugHighlightPolyHeaderIdx >= 0 || m_debugHighlightAll)
   {
-    if ((P->header[g_testPolyHeaderIdx] & g_testPolyHeaderMask))
+    if ((P->header[m_debugHighlightPolyHeaderIdx] & m_debugHighlightPolyHeaderMask) || m_debugHighlightAll)
     {
       r = 0.;
       g = 1.;
diff --git a/Src/OSD/SDL/Main.cpp b/Src/OSD/SDL/Main.cpp
index 3cb5089..a20b90d 100644
--- a/Src/OSD/SDL/Main.cpp
+++ b/Src/OSD/SDL/Main.cpp
@@ -410,9 +410,6 @@ static void SaveFrameBuffer(const std::string &file)
   Util::WriteSurfaceToBMP<Util::RGBA8>(file, pixels.get(), totalXRes, totalYRes, true);
 }
 
-bool g_forceFlushModels = false;
-int g_testPolyHeaderIdx = -1;
-uint32_t g_testPolyHeaderMask = 0;
 static std::string s_gfxStatePath;
   
 static std::string GetFileBaseName(const std::string &file)
@@ -439,24 +436,54 @@ static void TestPolygonHeaderBits(IEmulator *Emu)
     0xffffff60,
     0xff0300ff  // contour, luminous, etc.
   };
+  
+  const std::vector<uint32_t> unknownCullingNodeBits
+  {
+    0xffffffff,
+    0x00000000,
+    0x00000000,
+    0x00000000,
+    0x00000000,
+    0x00000000,
+    0x00000000,
+    0x00000000,
+    0x00000000,
+    0x00000000
+  };
 
   GLint readBuffer;
   glGetIntegerv(GL_READ_BUFFER, &readBuffer);
   glReadBuffer(GL_FRONT);
 
   // Render separate image for each unknown bit
-  g_forceFlushModels = true;
+  s_runtime_config.Set("Debug/ForceFlushModels", true);
   for (int idx = 0; idx < 7; idx++)
   {
     for (int bit = 0; bit < 32; bit++)
     {
       uint32_t mask = 1 << bit;
-      g_testPolyHeaderIdx = idx;
-      g_testPolyHeaderMask = mask;
+      s_runtime_config.Set("Debug/HighlightPolyHeaderIdx", idx);
+      s_runtime_config.Set("Debug/HighlightPolyHeaderMask", mask);
       if ((unknownPolyBits[idx] & mask))
       {
         Emu->RenderFrame();
-        std::string file = Util::Format() << "Analysis/" << GetFileBaseName(s_gfxStatePath) << "." << idx << "_" << Util::Hex(mask) << ".bmp";
+        std::string file = Util::Format() << "Analysis/" << GetFileBaseName(s_gfxStatePath) << "." << "poly" << "." << idx << "_" << Util::Hex(mask) << ".bmp";
+        SaveFrameBuffer(file);
+      }
+    }
+  }
+  
+  for (int idx = 0; idx < 10; idx++)
+  {
+    for (int bit = 0; bit < 32; bit++)
+    {
+      uint32_t mask = 1 << bit;
+      s_runtime_config.Set("Debug/HighlightCullingNodeIdx", idx);
+      s_runtime_config.Set("Debug/HighlightCullingNodeMask", mask);
+      if ((unknownCullingNodeBits[idx] & mask))
+      {
+        Emu->RenderFrame();
+        std::string file = Util::Format() << "Analysis/" << GetFileBaseName(s_gfxStatePath) << "." << "culling" << "." << idx << "_" << Util::Hex(mask) << ".bmp";
         SaveFrameBuffer(file);
       }
     }
@@ -473,7 +500,8 @@ static void TestPolygonHeaderBits(IEmulator *Emu)
   {
     std::string contents = s_polyAnalysisHTMLPrologue;
     contents += "    var g_file_base_name = '" + GetFileBaseName(s_gfxStatePath) + "';\n";  
-    contents += "    var g_unknown_bits = [" + std::string(Util::Format(",").Join(unknownPolyBits)) + "];\n";
+    contents += "    var g_unknown_poly_bits = [" + std::string(Util::Format(",").Join(unknownPolyBits)) + "];\n";
+    contents += "    var g_unknown_culling_bits = [" + std::string(Util::Format(",").Join(unknownCullingNodeBits)) + "];\n";
     contents += s_polyAnalysisHTMLEpilogue;
     fs << contents;
     printf("Produced: %s\n", file.c_str());
diff --git a/Src/OSD/SDL/PolyAnalysis.h b/Src/OSD/SDL/PolyAnalysis.h
index ffc1a14..5156824 100644
--- a/Src/OSD/SDL/PolyAnalysis.h
+++ b/Src/OSD/SDL/PolyAnalysis.h
@@ -33,6 +33,7 @@ static const char s_polyAnalysisHTMLPrologue[] =
   "<html>\n"
   "<head>\n"
   "  <style>\n"
+  "    left { float: left; }\n"
   "    table { table-layout: fixed; }\n"
   "    td { border: 1px solid black; width: 1em; }\n"
   "    td.nonselectable { background-color: gray; }\n"
@@ -42,10 +43,13 @@ static const char s_polyAnalysisHTMLPrologue[] =
   "  <script src='https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js'></script>\n"
   "</head>\n"
   "<body>\n"
-  "  <div id='Header'></div>\n"
+  "  <div id='Header'>\n"
+  "    <div id='PolyBits' class='left'></div>\n"
+  "    <div id='CullingBits' class='left'></div>\n"
+  "  </div>\n"
   "  <div><img id='Image' /></div>\n"
   "  <script>\n"
-  // Insert g_file_base_name and g_unknown bits here, then append epilogue
+  // Insert g_file_base_name, g_unknown_poly_bits, and g_unknown_culling_bits here, then append epilogue
 };
 
 static const char s_polyAnalysisHTMLEpilogue[] =
@@ -54,27 +58,28 @@ static const char s_polyAnalysisHTMLEpilogue[] =
   "    {\n"
   "      return '0x' + ('0000000'+Number(val).toString(16)).slice(-8);\n"
   "    }\n"
-  "    function getOnClickHandler(table, td, word, mask)\n"
+
+  "    function createOnClickHandler(type, table, td, word, mask)\n"
   "    {\n"
   "      return function()\n"
   "      {\n"
-  "        var file = g_file_base_name + '.' + word + '_' + hex32(mask) + '.bmp';\n"
-  "        table.find('td').removeClass('selected'); // remove from all cells\n"
+  "        var file = g_file_base_name + '.' + type + '.' + word + '_' + hex32(mask) + '.bmp';\n"
+  "        $('td').removeClass('selected'); // remove from all cells\n"
   "        td.addClass('selected');\n"
   "        $('#Image').empty();\n"
   "        $('#Image').attr('src', file);\n"
   "      };\n"
   "    }\n"
-  "    $(document).ready(function()\n"
+
+  "    function buildTable(num_words, type, unknown_bits)\n"
   "    {\n"
-  "      // Construct table\n"
   "      var table = $('<table></table>');\n"
   "      var bits_tr = $('<tr></tr>');   // first row will be bit legend\n"
   "      bits_tr.append($('<td></td>')); // column for word numbers\n"
   "      for (var bit = 31; bit >= 0; bit--)\n"
   "        bits_tr.append($('<td>'+bit+'</td>'));\n"
   "      table.append(bits_tr);\n"
-  "      for (var word = 0; word < 7; word++)\n"
+  "      for (var word = 0; word < num_words; word++)\n"
   "      {\n"
   "        var tr = $('<tr></tr>');\n"
   "        tr.append($('<td>'+word+'</td>'));\n"
@@ -82,15 +87,28 @@ static const char s_polyAnalysisHTMLEpilogue[] =
   "        {\n"
   "          var mask = 1 << bit;\n"
   "          var td = $('<td></td>');\n"
-  "          if (g_unknown_bits[word] & mask)\n"
-  "            td.addClass('selectable').click(getOnClickHandler(table, td, word, mask));\n"
+  "          if (unknown_bits[word] & mask)\n"
+  "            td.addClass('selectable').click(createOnClickHandler(type, table, td, word, mask));\n"
   "          else\n"
   "            td.addClass('nonselectable');\n"
   "          tr.append(td);\n"
   "        }\n"
   "        table.append(tr);\n"
   "      }\n"
-  "      $('#Header').append(table);\n"
+  "      return table;"
+  "    }\n"
+
+  "    $(document).ready(function()\n"
+  "    {\n"
+  "      // Construct tables\n"
+  "      var poly_table = buildTable(7, 'poly', g_unknown_poly_bits);\n"
+  "      var poly_title = $('<p></p>').text('Polygon Header');\n"
+  "      $('#PolyBits').append(poly_title);\n"
+  "      $('#PolyBits').append(poly_table);\n"
+  "      var culling_table = buildTable(10, 'culling', g_unknown_culling_bits);\n"
+  "      var culling_title = $('<p></p>').text('Culling Node');\n"
+  "      $('#CullingBits').append(culling_title);\n"
+  "      $('#CullingBits').append(culling_table);\n"
   "    });\n"
   "  </script>\n"
   "</body>\n"