diff --git a/common/custom_data/TFrag3Data.cpp b/common/custom_data/TFrag3Data.cpp
index cd46ba29e..d850dd720 100644
--- a/common/custom_data/TFrag3Data.cpp
+++ b/common/custom_data/TFrag3Data.cpp
@@ -233,6 +233,10 @@ void Texture::serialize(Serializer& ser) {
   ser.from_ptr(&load_to_pool);
 }
 
+void CollisionMesh::serialize(Serializer& ser) {
+  ser.from_pod_vector(&vertices);
+}
+
 void Level::serialize(Serializer& ser) {
   ser.from_ptr(&version);
   if (ser.is_loading() && version != TFRAG3_VERSION) {
@@ -282,6 +286,8 @@ void Level::serialize(Serializer& ser) {
     tree.serialize(ser);
   }
 
+  collision.serialize(ser);
+
   ser.from_ptr(&version2);
   if (ser.is_loading() && version2 != TFRAG3_VERSION) {
     ASSERT_MSG(false, fmt::format(
@@ -352,6 +358,9 @@ std::array<int, MemoryUsageCategory::NUM_CATEGORIES> Level::get_memory_usage() c
     result[SHRUB_IND] += sizeof(u32) * shrub_tree.indices.size();
   }
 
+  // collision
+  result[COLLISION] += sizeof(CollisionMesh::Vertex) * collision.vertices.size();
+
   return result;
 }
 
diff --git a/common/custom_data/Tfrag3Data.h b/common/custom_data/Tfrag3Data.h
index 50a895a55..a22a1dbd1 100644
--- a/common/custom_data/Tfrag3Data.h
+++ b/common/custom_data/Tfrag3Data.h
@@ -44,10 +44,13 @@ enum MemoryUsageCategory {
   SHRUB_TIME_OF_DAY,
   SHRUB_VERT,
   SHRUB_IND,
+
+  COLLISION,
+
   NUM_CATEGORIES
 };
 
-constexpr int TFRAG3_VERSION = 14;
+constexpr int TFRAG3_VERSION = 15;
 
 // These vertices should be uploaded to the GPU at load time and don't change
 struct PreloadedVertex {
@@ -306,6 +309,18 @@ struct ShrubTree {
   void unpack();
 };
 
+struct CollisionMesh {
+  struct Vertex {
+    float x, y, z;
+    u32 flags;
+    s16 nx, ny, nz;
+    u16 pad;
+  };
+  static_assert(sizeof(Vertex) == 24);
+  std::vector<Vertex> vertices;
+  void serialize(Serializer& ser);
+};
+
 constexpr int TFRAG_GEOS = 3;
 constexpr int TIE_GEOS = 4;
 
@@ -316,6 +331,7 @@ struct Level {
   std::array<std::vector<TfragTree>, TFRAG_GEOS> tfrag_trees;
   std::array<std::vector<TieTree>, TIE_GEOS> tie_trees;
   std::vector<ShrubTree> shrub_trees;
+  CollisionMesh collision;
   u16 version2 = TFRAG3_VERSION;
   void serialize(Serializer& ser);
 
diff --git a/common/math/Vector.h b/common/math/Vector.h
index 6774f64bb..bb0ba31a1 100644
--- a/common/math/Vector.h
+++ b/common/math/Vector.h
@@ -96,6 +96,13 @@ class Vector {
     return *this;
   }
 
+  Vector<T, Size>& operator-=(const Vector<T, Size>& other) {
+    for (int i = 0; i < Size; i++) {
+      m_data[i] -= other[i];
+    }
+    return *this;
+  }
+
   Vector<T, Size> elementwise_multiply(const Vector<T, Size>& other) const {
     Vector<T, Size> result;
     for (int i = 0; i < Size; i++) {
diff --git a/decompiler/CMakeLists.txt b/decompiler/CMakeLists.txt
index 1f64eabc2..c623693a4 100644
--- a/decompiler/CMakeLists.txt
+++ b/decompiler/CMakeLists.txt
@@ -51,10 +51,11 @@ add_library(
         IR2/LabelDB.cpp
         IR2/OpenGoalMapping.cpp
 
+        level_extractor/BspHeader.cpp
+        level_extractor/extract_collide_frags.cpp
         level_extractor/extract_level.cpp
         level_extractor/extract_tfrag.cpp
         level_extractor/extract_tie.cpp
-        level_extractor/BspHeader.cpp
         level_extractor/extract_shrub.cpp
 
         ObjectFile/LinkedObjectFile.cpp
diff --git a/decompiler/config.cpp b/decompiler/config.cpp
index 9654568f2..75324c5b2 100644
--- a/decompiler/config.cpp
+++ b/decompiler/config.cpp
@@ -67,6 +67,7 @@ Config read_config_file(const std::string& path_to_config_file,
   config.generate_symbol_definition_map = cfg.at("generate_symbol_definition_map").get<bool>();
   config.is_pal = cfg.at("is_pal").get<bool>();
   config.rip_levels = cfg.at("levels_convert_to_obj").get<bool>();
+  config.extract_collision = cfg.at("extract_collision").get<bool>();
 
   auto allowed = cfg.at("allowed_objects").get<std::vector<std::string>>();
   for (const auto& x : allowed) {
diff --git a/decompiler/config.h b/decompiler/config.h
index 52a61c6e2..876ade06b 100644
--- a/decompiler/config.h
+++ b/decompiler/config.h
@@ -100,6 +100,7 @@ struct Config {
   bool process_game_text = false;
   bool process_game_count = false;
   bool rip_levels = false;
+  bool extract_collision = false;
 
   bool write_hex_near_instructions = false;
   bool hexdump_code = false;
diff --git a/decompiler/config/jak1_ntsc_black_label.jsonc b/decompiler/config/jak1_ntsc_black_label.jsonc
index 2c9038279..517131699 100644
--- a/decompiler/config/jak1_ntsc_black_label.jsonc
+++ b/decompiler/config/jak1_ntsc_black_label.jsonc
@@ -86,5 +86,8 @@
   // turn this on to extract level background graphics data
   "levels_extract": true,
   // turn this on if you want extracted levels to be saved out as .obj files
-  "levels_convert_to_obj": false
+  "levels_convert_to_obj": false,
+  // should we extract collision meshes?
+  // these can be displayed in game, but makes the .fr3 files slightly larger
+  "extract_collision": true
 }
diff --git a/decompiler/extractor/main.cpp b/decompiler/extractor/main.cpp
index 943352bec..702155bdb 100644
--- a/decompiler/extractor/main.cpp
+++ b/decompiler/extractor/main.cpp
@@ -290,7 +290,7 @@ void decompile(std::filesystem::path jak1_input_files) {
   // levels
   {
     extract_all_levels(db, tex_db, config.levels_to_extract, "GAME.CGO", config.hacks,
-                       config.rip_levels);
+                       config.rip_levels, config.extract_collision);
   }
 }
 
diff --git a/decompiler/level_extractor/BspHeader.cpp b/decompiler/level_extractor/BspHeader.cpp
index e27016785..1247c3218 100644
--- a/decompiler/level_extractor/BspHeader.cpp
+++ b/decompiler/level_extractor/BspHeader.cpp
@@ -59,6 +59,14 @@ std::string Vector::print_meters(int indent) const {
   return result;
 }
 
+std::string Vector::print_decimal(int indent) const {
+  s32 d[4];
+  memcpy(d, data, 16);
+  std::string is(indent, ' ');
+  std::string result;
+  result += fmt::format("{}<vector {:d} {:d} {:d} {:d}>\n", is, d[0], d[1], d[2], d[3]);
+  return result;
+}
 void FileInfo::read_from_file(TypedRef ref, const decompiler::DecompilerTypeSystem& dts) {
   file_type = read_type_field(ref, "file-type", dts, true);
   file_name = read_string_field(ref, "file-name", dts, true);
@@ -887,6 +895,15 @@ void PrototypeBucketTie::read_from_file(TypedRef ref,
   dists.read_from_file(get_field_ref(ref, "dists", dts));
   rdists.read_from_file(get_field_ref(ref, "rdists", dts));
   stiffness = read_plain_data_field<float>(ref, "stiffness", dts);
+  auto fr = get_field_ref(ref, "collide-frag", dts);
+  {
+    const auto& word = fr.data->words_by_seg.at(fr.seg).at(fr.byte_offset / 4);
+    if (word.kind() == decompiler::LinkedWord::PTR) {
+      auto p = deref_label(fr);
+      p.byte_offset -= 4;
+      collide_frag.read_from_file(typed_ref_from_basic(p, dts), dts, stats);
+    }
+  }
 
   auto next_slot = get_field_ref(ref, "next", dts);
   for (int i = 0; i < 4; i++) {
@@ -1117,6 +1134,120 @@ std::string DrawableTreeInstanceTie::my_type() const {
   return "drawable-tree-instance-tie";
 }
 
+void DrawableTreeCollideFragment::read_from_file(TypedRef ref,
+                                                 const decompiler::DecompilerTypeSystem& dts,
+                                                 DrawStats* stats) {
+  s16 length = read_plain_data_field<s16>(ref, "length", dts);
+  auto data_ref = get_field_ref(ref, "data", dts);
+  if ((data_ref.byte_offset % 4) != 0) {
+    throw Error("misaligned data array");
+  }
+
+  Ref array_slot_ref = data_ref;
+  array_slot_ref.byte_offset += (length - 1) * 4;
+
+  Ref object_ref = deref_label(array_slot_ref);
+  object_ref.byte_offset -= 4;
+  last_array.read_from_file(typed_ref_from_basic(object_ref, dts), dts, stats);
+}
+
+std::string DrawableTreeCollideFragment::print(const PrintSettings& settings, int indent) const {
+  return last_array.print(settings, indent);
+}
+
+std::string DrawableTreeCollideFragment::my_type() const {
+  return "drawable-tree-collide-fragment";
+}
+
+void DrawableInlineArrayCollideFragment::read_from_file(TypedRef ref,
+                                                        const decompiler::DecompilerTypeSystem& dts,
+                                                        DrawStats* stats) {
+  ASSERT(ref.type->get_name() == "drawable-inline-array-collide-fragment");
+  id = read_plain_data_field<s16>(ref, "id", dts);
+  length = read_plain_data_field<s16>(ref, "length", dts);
+  bsphere.read_from_file(get_field_ref(ref, "bsphere", dts));
+
+  auto data_ref = get_field_ref(ref, "data", dts);
+  for (int i = 0; i < length; i++) {
+    Ref obj_ref = data_ref;
+    obj_ref.byte_offset += 32 * i;  // todo not a constant here
+    auto type = get_type_of_basic(obj_ref);
+    if (type != "collide-fragment") {
+      throw Error("bad collide fragment type: {}", type);
+    }
+    collide_fragments.emplace_back();
+    collide_fragments.back().read_from_file(typed_ref_from_basic(obj_ref, dts), dts, stats);
+  }
+}
+
+std::string DrawableInlineArrayCollideFragment::print(const PrintSettings& settings,
+                                                      int indent) const {
+  std::string is(indent, ' ');
+  std::string result;
+  int next_indent = indent + 4;
+  result += fmt::format("{}id: {}\n", is, id);
+  result += fmt::format("{}length: {}\n", is, length);
+  result += fmt::format("{}bsphere: {}", is, bsphere.print_meters());
+
+  if (settings.expand_collide) {
+    for (u32 i = 0; i < collide_fragments.size(); i++) {
+      result += fmt::format("{}data [{}]:\n", is, i);
+      result += collide_fragments[i].print(settings, next_indent);
+    }
+  }
+  return result;
+}
+
+std::string DrawableInlineArrayCollideFragment::my_type() const {
+  return "drawable-inline-array-collide-fragment";
+}
+
+void CollideFragment::read_from_file(TypedRef ref,
+                                     const decompiler::DecompilerTypeSystem& dts,
+                                     DrawStats* stats) {
+  bsphere.read_from_file(get_field_ref(ref, "bsphere", dts));
+  auto r = deref_label(get_field_ref(ref, "mesh", dts));
+  r.byte_offset -= 4;
+  mesh.read_from_file(typed_ref_from_basic(r, dts), dts, stats);
+}
+
+std::string CollideFragment::print(const PrintSettings& settings, int indent) const {
+  std::string is(indent, ' ');
+  std::string result;
+  result += fmt::format("{}bsphere: {}", is, bsphere.print_meters());
+  result += mesh.print(settings, indent);
+
+  return result;
+}
+
+void CollideFragMesh::read_from_file(TypedRef ref,
+                                     const decompiler::DecompilerTypeSystem& dts,
+                                     DrawStats* stats) {
+  strip_data_len = read_plain_data_field<u16>(ref, "strip-data-len", dts);
+  poly_count = read_plain_data_field<u16>(ref, "poly-count", dts);
+  vertex_count = read_plain_data_field<u8>(ref, "vertex-count", dts);
+  vertex_data_qwc = read_plain_data_field<u8>(ref, "vertex-data-qwc", dts);
+  total_qwc = read_plain_data_field<u8>(ref, "total-qwc", dts);
+  base_trans.read_from_file(get_field_ref(ref, "base-trans", dts));
+  base_trans.data[3] = 0;
+
+  packed_data = deref_label(get_field_ref(ref, "packed-data", dts));
+  pat_array = deref_label(get_field_ref(ref, "pat-array", dts));
+}
+
+std::string CollideFragMesh::print(const PrintSettings& settings, int indent) const {
+  std::string is(indent, ' ');
+  std::string result;
+  result += fmt::format("{}strip-data-len: {}\n", is, strip_data_len);
+  result += fmt::format("{}poly-count: {}\n", is, poly_count);
+  result += fmt::format("{}vertex-count: {}\n", is, vertex_count);
+  result += fmt::format("{}vertex-data-qwc: {}\n", is, vertex_data_qwc);
+  result += fmt::format("{}total-qwc: {}\n", is, total_qwc);
+  result += fmt::format("{}base-trans: {}", is, base_trans.print_decimal());
+
+  return result;
+}
+
 //////////////////////////
 // shrub
 //////////////////////////
@@ -1584,6 +1715,13 @@ std::unique_ptr<DrawableTree> make_drawable_tree(TypedRef ref,
     tree->read_from_file(ref, dts, stats);
     return tree;
   }
+
+  if (ref.type->get_name() == "drawable-tree-collide-fragment") {
+    auto tree = std::make_unique<DrawableTreeCollideFragment>();
+    tree->read_from_file(ref, dts, stats);
+    return tree;
+  }
+
   auto tree = std::make_unique<DrawableTreeUnknown>();
   tree->read_from_file(ref, dts, stats);
   return tree;
diff --git a/decompiler/level_extractor/BspHeader.h b/decompiler/level_extractor/BspHeader.h
index 1aae78f48..815c78e9b 100644
--- a/decompiler/level_extractor/BspHeader.h
+++ b/decompiler/level_extractor/BspHeader.h
@@ -14,6 +14,9 @@ class DecompilerTypeSystem;
 }  // namespace decompiler
 
 namespace level_tools {
+
+u32 deref_u32(const Ref& ref, int word_offset);
+
 struct PrintSettings {
   bool print_tfrag = false;
   bool expand_draw_node = false;
@@ -23,7 +26,8 @@ struct PrintSettings {
   bool expand_drawable_tree_tie_proto_data = false;
   bool expand_drawable_tree_instance_tie = false;
   bool expand_drawable_tree_actor = false;
-  bool expand_shrub = true;
+  bool expand_shrub = false;
+  bool expand_collide = false;
 };
 
 struct DrawStats {
@@ -50,6 +54,7 @@ struct Vector {
 
   std::string print(int indent = 0) const;
   std::string print_meters(int indent = 0) const;
+  std::string print_decimal(int indent = 0) const;
 };
 
 // a matrix with 16-bit integers.
@@ -181,6 +186,68 @@ struct DrawableTreeActor : public DrawableTree {
   std::vector<std::unique_ptr<DrawableInlineArray>> arrays;
 };
 
+/////////////////////
+// Collision
+/////////////////////
+
+struct CollideFragMesh {
+  /*
+  ((packed-data     uint32         :offset-assert 4)
+   (pat-array       uint32         :offset-assert 8)
+   (strip-data-len  uint16         :offset-assert 12)
+   (poly-count      uint16         :offset-assert 14)
+   (base-trans      vector :inline :offset-assert 16)
+   ;; these go in the w of the vector above.
+   (vertex-count    uint8          :offset 28)
+   (vertex-data-qwc uint8          :offset 29)
+   (total-qwc       uint8          :offset 30)
+   (unused          uint8          :offset 31)
+   )
+   */
+  void read_from_file(TypedRef ref, const decompiler::DecompilerTypeSystem& dts, DrawStats* stats);
+  std::string print(const PrintSettings& settings, int indent) const;
+
+  u16 strip_data_len;
+  u16 poly_count;
+  // appears to be integers...
+  Vector base_trans;
+  u8 vertex_count;
+  u8 vertex_data_qwc;
+  u8 total_qwc;
+
+  Ref packed_data;
+  Ref pat_array;
+};
+
+struct CollideFragment {
+  void read_from_file(TypedRef ref, const decompiler::DecompilerTypeSystem& dts, DrawStats* stats);
+  std::string print(const PrintSettings& settings, int indent) const;
+  Vector bsphere;
+  CollideFragMesh mesh;
+};
+
+struct DrawableInlineArrayCollideFragment : public DrawableInlineArray {
+  void read_from_file(TypedRef ref,
+                      const decompiler::DecompilerTypeSystem& dts,
+                      DrawStats* stats) override;
+  std::string print(const PrintSettings& settings, int indent) const override;
+  std::string my_type() const override;
+  std::vector<CollideFragment> collide_fragments;
+  s16 id;
+  s16 length;
+  Vector bsphere;
+};
+
+struct DrawableTreeCollideFragment : public DrawableTree {
+  void read_from_file(TypedRef ref,
+                      const decompiler::DecompilerTypeSystem& dts,
+                      DrawStats* stats) override;
+  std::string print(const PrintSettings& settings, int indent) const override;
+  std::string my_type() const override;
+
+  DrawableInlineArrayCollideFragment last_array;
+};
+
 /////////////////////
 // TFRAG
 /////////////////////
@@ -382,6 +449,7 @@ struct PrototypeBucketTie {
 
   // todo envmap shader
   // todo collide-frag
+  DrawableInlineArrayCollideFragment collide_frag;
   // todo tie-colors
   // todo data
 
diff --git a/decompiler/level_extractor/extract_collide_frags.cpp b/decompiler/level_extractor/extract_collide_frags.cpp
new file mode 100644
index 000000000..17bd995dc
--- /dev/null
+++ b/decompiler/level_extractor/extract_collide_frags.cpp
@@ -0,0 +1,280 @@
+#include "extract_collide_frags.h"
+
+#include "common/util/FileUtil.h"
+
+namespace decompiler {
+
+struct CollideListItem {
+  const level_tools::CollideFragMesh* mesh = nullptr;
+  const level_tools::InstanceTie* inst = nullptr;
+
+  struct {
+    std::vector<math::Vector4f> vu0_buffer;
+    std::vector<math::Vector<u8, 3>> faces;
+  } unpacked;
+};
+
+/*!
+ * Get all collide frags.
+ */
+std::vector<CollideListItem> build_all_frags_list(
+    const level_tools::DrawableTreeCollideFragment* tree,
+    const std::vector<const level_tools::DrawableTreeInstanceTie*>& ties) {
+  std::vector<CollideListItem> list;
+  for (auto& cf : tree->last_array.collide_fragments) {
+    auto& elt = list.emplace_back();
+    elt.mesh = &cf.mesh;
+    elt.inst = nullptr;
+  }
+
+  for (auto tt : ties) {
+    auto last_array = tt->arrays.back().get();
+    auto as_instance_array = dynamic_cast<level_tools::DrawableInlineArrayInstanceTie*>(last_array);
+    ASSERT(as_instance_array);
+    for (auto& inst : as_instance_array->instances) {
+      auto& frags = tt->prototypes.prototype_array_tie.data.at(inst.bucket_index)
+                        .collide_frag.collide_fragments;
+      for (auto& frag : frags) {
+        auto& elt = list.emplace_back();
+        elt.inst = &inst;
+        elt.mesh = &frag.mesh;
+      }
+    }
+  }
+  return list;
+}
+
+float u32_to_float(u32 in) {
+  float r;
+  memcpy(&r, &in, sizeof(float));
+  return r;
+}
+
+u16 deref_u16(const Ref& ref, int array_idx) {
+  u32 u32_offset = array_idx / 2;
+  u32 u32_val = level_tools::deref_u32(ref, u32_offset);
+  if (array_idx & 1) {
+    return u32_val >> 16;
+  } else {
+    return (u16)u32_val;
+  }
+}
+
+s8 deref_s8(const Ref& ref, int byte) {
+  u32 u32_offset = byte / 4;
+  u32 u32_val = level_tools::deref_u32(ref, u32_offset);
+  s8 vals[4];
+  memcpy(vals, &u32_val, 4);
+  return vals[byte & 3];
+}
+
+void unpack_part1_collide_list_item(CollideListItem& item) {
+  int in_idx = 0;
+  int out_idx = 0;
+  int qw_to_write = item.mesh->vertex_count;
+
+  while (out_idx < qw_to_write * 4) {
+    auto& vert = item.unpacked.vu0_buffer.emplace_back();
+    vert[0] = u32_to_float(0x4d000000 + deref_u16(item.mesh->packed_data, in_idx++));
+    vert[1] = u32_to_float(0x4d000000 + deref_u16(item.mesh->packed_data, in_idx++));
+    vert[2] = u32_to_float(0x4d000000 + deref_u16(item.mesh->packed_data, in_idx++));
+    vert[3] = u32_to_float(0x3f800000);
+    out_idx += 4;
+  }
+}
+
+math::Vector<float, 4> transform_tie(const std::array<math::Vector4f, 4> mat,
+                                     const math::Vector4f& pt) {
+  auto temp = mat[0] * pt.x() + mat[1] * pt.y() + mat[2] * pt.z() + mat[3];
+  math::Vector4f result;
+  result.x() = temp.x();
+  result.y() = temp.y();
+  result.z() = temp.z();
+  result.w() = 1.f;
+  return result;
+}
+
+namespace {
+// todo dedup
+std::array<math::Vector4f, 4> extract_tie_matrix(const u16* data) {
+  std::array<math::Vector4f, 4> result;
+  for (int i = 0; i < 4; i++) {
+    s32 x = data[12 + i];
+    x <<= 16;
+    x >>= 10;
+    result[3][i] = x;
+  }
+
+  for (int vec = 0; vec < 3; vec++) {
+    for (int i = 0; i < 4; i++) {
+      s32 x = data[vec * 4 + i];
+      x <<= 16;
+      x >>= 16;
+      result[vec][i] = (float)x / 4096.f;
+    }
+  }
+
+  return result;
+}
+}  // namespace
+
+void unpack_part2_collide_list_item(CollideListItem& item) {
+  float base_offset = u32_to_float(0x4d000000);
+
+  math::Vector4f vf13_combo_offset(base_offset, base_offset, base_offset, 0);
+  s32 base_trans_int[4];
+  memcpy(base_trans_int, item.mesh->base_trans.data, 16);
+  math::Vector4f vf14_base_trans_float(base_trans_int[0], base_trans_int[1], base_trans_int[2],
+                                       base_trans_int[3]);
+  vf13_combo_offset -= vf14_base_trans_float;
+  std::array<math::Vector4f, 4> mat;
+  if (item.inst) {
+    mat = extract_tie_matrix(item.inst->origin.data);
+    mat[3][0] += item.inst->bsphere.data[0];
+    mat[3][1] += item.inst->bsphere.data[1];
+    mat[3][2] += item.inst->bsphere.data[2];
+  }
+
+  for (auto& ver : item.unpacked.vu0_buffer) {
+    ver -= vf13_combo_offset;
+    if (item.inst) {
+      ver = transform_tie(mat, ver);
+    }
+  }
+}
+
+void find_faces(CollideListItem& item) {
+  u32 byte_offset = 16 * item.mesh->vertex_data_qwc;
+
+  while (true) {
+    s8 t7_start_idx = deref_s8(item.mesh->packed_data, byte_offset++);
+    if (t7_start_idx < 0) {
+      return;
+    }
+    s8 t8_start_idx = deref_s8(item.mesh->packed_data, byte_offset++);
+    s8 t6_start_idx = deref_s8(item.mesh->packed_data, byte_offset++);
+
+    s8 t6_run_idx = t7_start_idx;
+    s8 t7_run_idx = t8_start_idx;
+    s8 ra_run_idx = t6_start_idx;
+
+    item.unpacked.faces.emplace_back(t6_run_idx, t7_run_idx, ra_run_idx);
+    s8 s5 = 1;
+    while (true) {
+      s8 next = deref_s8(item.mesh->packed_data, byte_offset++);
+      if (!next) {
+        break;
+      }
+      if (next < 0) {
+        next = -((s32)next);
+      } else {
+        t6_run_idx = t7_run_idx;
+        s5 = -s5;
+      }
+      next--;
+      t7_run_idx = ra_run_idx;
+      ra_run_idx = next;
+      u8 result[3];
+      result[1] = t7_run_idx;
+      result[1 + s5] = ra_run_idx;
+      result[1 - s5] = t6_run_idx;
+      item.unpacked.faces.emplace_back(result[0], result[1], result[2]);
+      ASSERT((u32)next < item.unpacked.vu0_buffer.size());
+    }
+  }
+}
+
+std::string debug_dump_to_obj(const std::vector<CollideListItem>& list) {
+  std::vector<math::Vector4f> verts;
+  std::vector<math::Vector<u32, 3>> faces;
+
+  for (auto& item : list) {
+    u32 f_off = verts.size() + 1;
+    for (auto& f : item.unpacked.faces) {
+      faces.emplace_back(f[0] + f_off, f[1] + f_off, f[2] + f_off);
+    }
+    for (u32 t = 0; t < item.unpacked.vu0_buffer.size(); t++) {
+      verts.push_back(item.unpacked.vu0_buffer[t] / 65536);
+    }
+  }
+
+  std::string result;
+  for (auto& vert : verts) {
+    result += fmt::format("v {} {} {}\n", vert.x(), vert.y(), vert.z());
+  }
+
+  for (auto& face : faces) {
+    result += fmt::format("f {}/{} {}/{} {}/{}\n", face.x(), face.x(), face.y(), face.y(), face.z(),
+                          face.z());
+  }
+
+  return result;
+}
+
+void set_vertices_for_tri(tfrag3::CollisionMesh::Vertex* out, const math::Vector4f* in) {
+  math::Vector3f v10 = in[1].xyz() - in[0].xyz();
+  math::Vector3f v20 = in[2].xyz() - in[0].xyz();
+  auto normal = (v10.cross(v20).normalized() * INT16_MAX).cast<s16>();
+
+  for (int i = 0; i < 3; i++) {
+    out[i].x = in[i].x();
+    out[i].y = in[i].y();
+    out[i].z = in[i].z();
+    out[i].nx = normal.x();
+    out[i].ny = normal.y();
+    out[i].nz = normal.z();
+    out[i].flags = 0;  // todo
+    out[i].pad = 0;
+  }
+}
+
+void extract_collide_frags(const level_tools::DrawableTreeCollideFragment* tree,
+                           const std::vector<const level_tools::DrawableTreeInstanceTie*>& ties,
+                           const std::string& debug_name,
+                           tfrag3::Level& out,
+                           bool dump_level) {
+  // in-game, the broad-phase collision builds a list of fragments, then unpacks them with:
+  /*
+   *(dotimes (i (-> *collide-list* num-items))
+      (let ((frag (-> *collide-list* items i)))
+          ;; to VU0 memory
+          (__pc-upload-collide-frag (-> frag mesh packed-data) (-> frag mesh vertex-data-qwc) (->
+   frag mesh vertex-count))
+          ;; from VU0 memory to scratchpad
+          (unpack-background-collide-mesh obj (-> frag mesh) (-> frag inst) 0)
+          ;; from scratchpad to collide-cache memory.
+          (import-mesh-func obj (-> frag mesh))
+        )
+      )
+   */
+
+  auto all_frags = build_all_frags_list(tree, ties);
+  u32 total_faces = 0;
+  for (auto& frag : all_frags) {
+    unpack_part1_collide_list_item(frag);
+    unpack_part2_collide_list_item(frag);
+    find_faces(frag);
+    total_faces += frag.unpacked.faces.size();
+  }
+
+  if (dump_level) {
+    auto debug_out = debug_dump_to_obj(all_frags);
+    file_util::write_text_file(
+        file_util::get_file_path({"debug_out", fmt::format("collide-{}.obj", debug_name)}),
+        debug_out);
+  }
+
+  for (auto& item : all_frags) {
+    for (auto& f : item.unpacked.faces) {
+      math::Vector4f verts[3] = {item.unpacked.vu0_buffer[f[0]], item.unpacked.vu0_buffer[f[1]],
+                                 item.unpacked.vu0_buffer[f[2]]};
+      tfrag3::CollisionMesh::Vertex out_verts[3];
+      set_vertices_for_tri(out_verts, verts);
+      for (int i = 0; i < 3; i++) {
+        out.collision.vertices.push_back(out_verts[i]);
+      }
+    }
+  }
+}
+
+}  // namespace decompiler
\ No newline at end of file
diff --git a/decompiler/level_extractor/extract_collide_frags.h b/decompiler/level_extractor/extract_collide_frags.h
new file mode 100644
index 000000000..44fc2bf44
--- /dev/null
+++ b/decompiler/level_extractor/extract_collide_frags.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include "BspHeader.h"
+#include "common/custom_data/Tfrag3Data.h"
+
+namespace decompiler {
+
+void extract_collide_frags(const level_tools::DrawableTreeCollideFragment* tree,
+                           const std::vector<const level_tools::DrawableTreeInstanceTie*>& ties,
+                           const std::string& debug_name,
+                           tfrag3::Level& out,
+                           bool dump_level);
+
+}  // namespace decompiler
\ No newline at end of file
diff --git a/decompiler/level_extractor/extract_level.cpp b/decompiler/level_extractor/extract_level.cpp
index 3889fa259..a43f028ef 100644
--- a/decompiler/level_extractor/extract_level.cpp
+++ b/decompiler/level_extractor/extract_level.cpp
@@ -6,6 +6,7 @@
 #include "decompiler/level_extractor/extract_tfrag.h"
 #include "decompiler/level_extractor/extract_tie.h"
 #include "decompiler/level_extractor/extract_shrub.h"
+#include "decompiler/level_extractor/extract_collide_frags.h"
 #include "common/util/compress.h"
 #include "common/util/FileUtil.h"
 #include "common/util/SimpleThreadGroup.h"
@@ -77,7 +78,8 @@ void print_memory_usage(const tfrag3::Level& lev, int uncompressed_data_size) {
       {"tfrag-bvh", memory_use_by_category[tfrag3::MemoryUsageCategory::TFRAG_BVH]},
       {"shrub-colors", memory_use_by_category[tfrag3::MemoryUsageCategory::SHRUB_TIME_OF_DAY]},
       {"shrub-vert", memory_use_by_category[tfrag3::MemoryUsageCategory::SHRUB_VERT]},
-      {"shrub-ind", memory_use_by_category[tfrag3::MemoryUsageCategory::SHRUB_IND]}};
+      {"shrub-ind", memory_use_by_category[tfrag3::MemoryUsageCategory::SHRUB_IND]},
+      {"collision", memory_use_by_category[tfrag3::MemoryUsageCategory::COLLISION]}};
   for (auto& known : known_categories) {
     total_accounted += known.second;
   }
@@ -166,7 +168,8 @@ void extract_from_level(const ObjectFileDB& db,
                         const TextureDB& tex_db,
                         const std::string& dgo_name,
                         const DecompileHacks& hacks,
-                        bool dump_level) {
+                        bool dump_level,
+                        bool extract_collision) {
   if (db.obj_files_by_dgo.count(dgo_name) == 0) {
     lg::warn("Skipping extract for {} because the DGO was not part of the input", dgo_name);
     return;
@@ -192,9 +195,9 @@ void extract_from_level(const ObjectFileDB& db,
 
   /*
   level_tools::PrintSettings settings;
-  settings.expand_shrub = true;
+  settings.expand_collide = true;
   fmt::print("{}\n", bsp_header.print(settings));
-  */
+   */
 
   const std::set<std::string> tfrag_trees = {
       "drawable-tree-tfrag",     "drawable-tree-trans-tfrag",  "drawable-tree-dirt-tfrag",
@@ -204,6 +207,15 @@ void extract_from_level(const ObjectFileDB& db,
 
   add_all_textures_from_level(tfrag_level, dgo_name, tex_db);
 
+  std::vector<const level_tools::DrawableTreeInstanceTie*> all_ties;
+  for (auto& draw_tree : bsp_header.drawable_tree_array.trees) {
+    auto as_tie_tree = dynamic_cast<level_tools::DrawableTreeInstanceTie*>(draw_tree.get());
+    if (as_tie_tree) {
+      all_ties.push_back(as_tie_tree);
+    }
+  }
+
+  bool got_collide = false;
   for (auto& draw_tree : bsp_header.drawable_tree_array.trees) {
     if (tfrag_trees.count(draw_tree->my_type())) {
       auto as_tfrag_tree = dynamic_cast<level_tools::DrawableTreeTfrag*>(draw_tree.get());
@@ -227,11 +239,21 @@ void extract_from_level(const ObjectFileDB& db,
       ASSERT(as_shrub_tree);
       extract_shrub(as_shrub_tree, fmt::format("{}-{}-shrub", dgo_name, i++),
                     bsp_header.texture_remap_table, tex_db, {}, tfrag_level, dump_level);
+    } else if (draw_tree->my_type() == "drawable-tree-collide-fragment" && extract_collision) {
+      auto as_collide_frags =
+          dynamic_cast<level_tools::DrawableTreeCollideFragment*>(draw_tree.get());
+      ASSERT(as_collide_frags);
+      ASSERT(!got_collide);
+      got_collide = true;
+      extract_collide_frags(as_collide_frags, all_ties, fmt::format("{}-{}-collide", dgo_name, i++),
+                            tfrag_level, dump_level);
     } else {
       // fmt::print("  unsupported tree {}\n", draw_tree->my_type());
     }
   }
 
+  tfrag_level.level_name = level_name;
+
   Serializer ser;
   tfrag_level.serialize(ser);
   auto compressed =
@@ -249,11 +271,14 @@ void extract_all_levels(const ObjectFileDB& db,
                         const std::vector<std::string>& dgo_names,
                         const std::string& common_name,
                         const DecompileHacks& hacks,
-                        bool debug_dump_level) {
+                        bool debug_dump_level,
+                        bool extract_collision) {
   extract_common(db, tex_db, common_name);
   SimpleThreadGroup threads;
   threads.run(
-      [&](int idx) { extract_from_level(db, tex_db, dgo_names[idx], hacks, debug_dump_level); },
+      [&](int idx) {
+        extract_from_level(db, tex_db, dgo_names[idx], hacks, debug_dump_level, extract_collision);
+      },
       dgo_names.size());
   threads.join();
 }
diff --git a/decompiler/level_extractor/extract_level.h b/decompiler/level_extractor/extract_level.h
index a97fcf37d..d09da915d 100644
--- a/decompiler/level_extractor/extract_level.h
+++ b/decompiler/level_extractor/extract_level.h
@@ -10,7 +10,8 @@ void extract_from_level(const ObjectFileDB& db,
                         const TextureDB& tex_db,
                         const std::string& dgo_name,
                         const DecompileHacks& hacks,
-                        bool dump_level);
+                        bool dump_level,
+                        bool extract_collision);
 void extract_common(const ObjectFileDB& db, const TextureDB& tex_db, const std::string& dgo_name);
 
 // extract everything
@@ -19,5 +20,6 @@ void extract_all_levels(const ObjectFileDB& db,
                         const std::vector<std::string>& dgo_names,
                         const std::string& common_name,
                         const DecompileHacks& hacks,
-                        bool debug_dump_level);
+                        bool debug_dump_level,
+                        bool extract_collision);
 }  // namespace decompiler
diff --git a/decompiler/main.cpp b/decompiler/main.cpp
index 99b49c73e..f7ce060da 100644
--- a/decompiler/main.cpp
+++ b/decompiler/main.cpp
@@ -210,7 +210,7 @@ int main(int argc, char** argv) {
 
   if (config.levels_extract) {
     extract_all_levels(db, tex_db, config.levels_to_extract, "GAME.CGO", config.hacks,
-                       config.rip_levels);
+                       config.rip_levels, config.extract_collision);
   }
 
   fmt::print("[Mem] After extraction: {} MB\n", get_peak_rss() / (1024 * 1024));
diff --git a/decompiler/util/goal_data_reader.cpp b/decompiler/util/goal_data_reader.cpp
index 9b216e28d..de4b7d64b 100644
--- a/decompiler/util/goal_data_reader.cpp
+++ b/decompiler/util/goal_data_reader.cpp
@@ -234,7 +234,8 @@ TypedRef typed_ref_from_basic(const Ref& object, const decompiler::DecompilerTyp
   const auto& word = object.data->words_by_seg.at(object.seg).at(byte_in_words / 4);
 
   if (word.kind() != decompiler::LinkedWord::TYPE_PTR) {
-    throw Error("typed_ref_from_basic did not get a type tag (offset {} words)", byte_in_words / 4);
+    throw Error("typed_ref_from_basic did not get a type tag (offset {} words). Got {}",
+                byte_in_words / 4, (int)word.kind());
   }
 
   TypedRef result;
@@ -252,7 +253,8 @@ Ref deref_label(const Ref& object) {
   const auto& word = object.data->words_by_seg.at(object.seg).at(byte_in_words / 4);
 
   if (word.kind() != decompiler::LinkedWord::PTR) {
-    throw Error("deref_label did not get a label (offset {} words)", byte_in_words / 4);
+    throw Error("deref_label did not get a label (offset {} words). Got {} {}", byte_in_words / 4,
+                (int)word.kind(), word.data);
   }
 
   const auto& lab = object.data->labels.at(word.label_id());
diff --git a/game/CMakeLists.txt b/game/CMakeLists.txt
index 52487f556..910573783 100644
--- a/game/CMakeLists.txt
+++ b/game/CMakeLists.txt
@@ -96,6 +96,7 @@ set(RUNTIME_SOURCE
         graphics/opengl_renderer/ocean/OceanTexture.cpp
         graphics/opengl_renderer/ocean/OceanTexture_PC.cpp
         graphics/opengl_renderer/BucketRenderer.cpp
+        graphics/opengl_renderer/CollideMeshRenderer.cpp
         graphics/opengl_renderer/debug_gui.cpp
         graphics/opengl_renderer/DirectRenderer.cpp
         graphics/opengl_renderer/DirectRenderer2.cpp
diff --git a/game/graphics/opengl_renderer/BucketRenderer.cpp b/game/graphics/opengl_renderer/BucketRenderer.cpp
index 7edc882e6..3a1d7bd56 100644
--- a/game/graphics/opengl_renderer/BucketRenderer.cpp
+++ b/game/graphics/opengl_renderer/BucketRenderer.cpp
@@ -59,7 +59,7 @@ void SkipRenderer::render(DmaFollower& dma,
 }
 
 void SharedRenderState::reset() {
-  has_camera_planes = false;
+  has_pc_data = false;
   for (auto& x : occlusion_vis) {
     x.valid = false;
   }
diff --git a/game/graphics/opengl_renderer/BucketRenderer.h b/game/graphics/opengl_renderer/BucketRenderer.h
index 77d9aea1f..a87f79fdf 100644
--- a/game/graphics/opengl_renderer/BucketRenderer.h
+++ b/game/graphics/opengl_renderer/BucketRenderer.h
@@ -43,11 +43,17 @@ struct SharedRenderState {
   math::Vector<u8, 4> fog_color;
   float fog_intensity = 1.f;
   bool no_multidraw = false;
+  bool render_collision_mesh = false;
 
   void reset();
-  bool has_camera_planes = false;
+  bool has_pc_data = false;
   LevelVis occlusion_vis[2];
+
   math::Vector4f camera_planes[4];
+  math::Vector4f camera_matrix[4];
+  math::Vector4f camera_hvdf_off;
+  math::Vector4f camera_fog;
+  math::Vector4f camera_pos;
 
   EyeRenderer* eye_renderer = nullptr;
 
diff --git a/game/graphics/opengl_renderer/CollideMeshRenderer.cpp b/game/graphics/opengl_renderer/CollideMeshRenderer.cpp
new file mode 100644
index 000000000..ac3b5fcfc
--- /dev/null
+++ b/game/graphics/opengl_renderer/CollideMeshRenderer.cpp
@@ -0,0 +1,97 @@
+#include "CollideMeshRenderer.h"
+
+#include "game/graphics/opengl_renderer/background/background_common.h"
+
+CollideMeshRenderer::CollideMeshRenderer() {
+  glGenVertexArrays(1, &m_vao);
+}
+
+CollideMeshRenderer::~CollideMeshRenderer() {
+  glDeleteVertexArrays(1, &m_vao);
+}
+
+void CollideMeshRenderer::render(SharedRenderState* render_state, ScopedProfilerNode& prof) {
+  if (!render_state->has_pc_data) {
+    return;
+  }
+
+  auto levels = render_state->loader->get_in_use_levels();
+  if (levels.empty()) {
+    return;
+  }
+  render_state->shaders[ShaderId::COLLISION].activate();
+
+  glBindVertexArray(m_vao);
+  TfragRenderSettings settings;
+  memcpy(settings.math_camera.data(), render_state->camera_matrix[0].data(), 64);
+  settings.hvdf_offset = render_state->camera_hvdf_off;
+  settings.fog = render_state->camera_fog;
+  settings.tree_idx = 0;
+  for (int i = 0; i < 4; i++) {
+    settings.planes[i] = render_state->camera_planes[i];
+  }
+  glUniformMatrix4fv(
+      glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "camera"), 1, GL_FALSE,
+      settings.math_camera.data());
+  glUniform4f(glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "hvdf_offset"),
+              settings.hvdf_offset[0], settings.hvdf_offset[1], settings.hvdf_offset[2],
+              settings.hvdf_offset[3]);
+  const auto& trans = render_state->camera_pos;
+  glUniform4f(
+      glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "camera_position"),
+      trans[0], trans[1], trans[2], trans[3]);
+  glUniform1f(glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "fog_constant"),
+              settings.fog.x());
+  glUniform1f(glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "fog_min"),
+              settings.fog.y());
+  glUniform1f(glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "fog_max"),
+              settings.fog.z());
+  glUniform1i(glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "mode"), 0);
+  glEnable(GL_DEPTH_TEST);
+  glDepthFunc(GL_GEQUAL);
+  glEnable(GL_BLEND);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);  // ?
+  glDepthMask(GL_TRUE);
+
+  for (auto lev : levels) {
+    glBindBuffer(GL_ARRAY_BUFFER, lev->collide_vertices);
+    glEnableVertexAttribArray(0);
+    glEnableVertexAttribArray(1);
+    glEnableVertexAttribArray(2);
+    glVertexAttribPointer(0,                                      // location 0 in the shader
+                          3,                                      // 3 values per vert
+                          GL_FLOAT,                               // floats
+                          GL_FALSE,                               // normalized
+                          sizeof(tfrag3::CollisionMesh::Vertex),  // stride
+                          0                                       // offset (0)
+    );
+    glVertexAttribIPointer(1,                                      // location 1 in the shader
+                           1,                                      // 3 values per vert
+                           GL_UNSIGNED_INT,                        // u32
+                           sizeof(tfrag3::CollisionMesh::Vertex),  // stride
+                           (void*)offsetof(tfrag3::CollisionMesh::Vertex, flags)  // offset
+    );
+    glVertexAttribPointer(2,                                      // location 2 in the shader
+                          3,                                      // 3 values per vert
+                          GL_SHORT,                               // floats
+                          GL_TRUE,                                // normalized
+                          sizeof(tfrag3::CollisionMesh::Vertex),  // stride
+                          (void*)offsetof(tfrag3::CollisionMesh::Vertex, nx)  // offset (0)
+    );
+    glUniform1i(glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "mode"), 0);
+    glDrawArrays(GL_TRIANGLES, 0, lev->level->collision.vertices.size());
+
+    bool kDrawWireframe = false;
+    if (kDrawWireframe) {
+      glUniform1i(glGetUniformLocation(render_state->shaders[ShaderId::COLLISION].id(), "mode"), 1);
+      glDisable(GL_BLEND);
+      glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+      glDrawArrays(GL_TRIANGLES, 0, lev->level->collision.vertices.size());
+      glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+      glEnable(GL_BLEND);
+    }
+
+    prof.add_draw_call();
+    prof.add_tri(lev->level->collision.vertices.size() / 3);
+  }
+}
\ No newline at end of file
diff --git a/game/graphics/opengl_renderer/CollideMeshRenderer.h b/game/graphics/opengl_renderer/CollideMeshRenderer.h
new file mode 100644
index 000000000..13bb1c420
--- /dev/null
+++ b/game/graphics/opengl_renderer/CollideMeshRenderer.h
@@ -0,0 +1,12 @@
+#pragma once
+#include "game/graphics/opengl_renderer/BucketRenderer.h"
+
+class CollideMeshRenderer {
+ public:
+  CollideMeshRenderer();
+  void render(SharedRenderState* render_state, ScopedProfilerNode& prof);
+  ~CollideMeshRenderer();
+
+ private:
+  GLuint m_vao;
+};
diff --git a/game/graphics/opengl_renderer/Loader.cpp b/game/graphics/opengl_renderer/Loader.cpp
index 71b99cdc8..70dd3a0cc 100644
--- a/game/graphics/opengl_renderer/Loader.cpp
+++ b/game/graphics/opengl_renderer/Loader.cpp
@@ -75,6 +75,21 @@ void Loader::set_want_levels(const std::vector<std::string>& levels) {
   }
 }
 
+/*!
+ * Get all levels that are in memory and used very recently.
+ */
+std::vector<Loader::LevelData*> Loader::get_in_use_levels() {
+  std::vector<Loader::LevelData*> result;
+  std::unique_lock<std::mutex> lk(m_loader_mutex);
+
+  for (auto& lev : m_loaded_tfrag3_levels) {
+    if (lev.second.frames_since_last_used < 5) {
+      result.push_back(&lev.second.data);
+    }
+  }
+  return result;
+}
+
 /*!
  * Loader function that runs in a completely separate thread.
  * This is used for file I/O and unpacking.
@@ -474,6 +489,15 @@ bool Loader::init_tie(Timer& timer, LevelData& data) {
   return false;
 }
 
+bool Loader::init_collide(Timer& /*timer*/, LevelData& data) {
+  glGenBuffers(1, &data.collide_vertices);
+  glBindBuffer(GL_ARRAY_BUFFER, data.collide_vertices);
+  glBufferData(GL_ARRAY_BUFFER,
+               data.level->collision.vertices.size() * sizeof(tfrag3::CollisionMesh::Vertex),
+               data.level->collision.vertices.data(), GL_STATIC_DRAW);
+  return true;
+}
+
 bool Loader::upload_textures(Timer& timer, LevelData& data, TexturePool& texture_pool) {
   // try to move level from initializing to initialized:
 
@@ -583,12 +607,14 @@ void Loader::update(TexturePool& texture_pool) {
         if (init_tie(loader_timer, lev.data)) {
           if (init_tfrag(loader_timer, lev.data)) {
             if (init_shrub(loader_timer, lev.data)) {
-              // we're done! lock before removing from loaded.
-              lk.lock();
-              it->second.data.load_id = m_id++;
+              if (init_collide(loader_timer, lev.data)) {
+                // we're done! lock before removing from loaded.
+                lk.lock();
+                it->second.data.load_id = m_id++;
 
-              m_loaded_tfrag3_levels[name] = std::move(lev);
-              m_initializing_tfrag3_levels.erase(it);
+                m_loaded_tfrag3_levels[name] = std::move(lev);
+                m_initializing_tfrag3_levels.erase(it);
+              }
             }
           }
         }
@@ -640,6 +666,8 @@ void Loader::update(TexturePool& texture_pool) {
             }
           }
 
+          glDeleteBuffers(1, &lev.second.data.collide_vertices);
+
           m_loaded_tfrag3_levels.erase(lev.first);
           break;
         }
diff --git a/game/graphics/opengl_renderer/Loader.h b/game/graphics/opengl_renderer/Loader.h
index b03f31c30..70577752b 100644
--- a/game/graphics/opengl_renderer/Loader.h
+++ b/game/graphics/opengl_renderer/Loader.h
@@ -31,6 +31,7 @@ class Loader {
     std::array<std::vector<TieOpenGL>, tfrag3::TIE_GEOS> tie_data;
     std::array<std::vector<GLuint>, tfrag3::TIE_GEOS> tfrag_vertex_data;
     std::vector<GLuint> shrub_vertex_data;
+    GLuint collide_vertices;
 
     // internal load state
     bool tie_opengl_created = false;
@@ -56,6 +57,7 @@ class Loader {
   const LevelData* get_tfrag3_level(const std::string& level_name);
   void load_common(TexturePool& tex_pool, const std::string& name);
   void set_want_levels(const std::vector<std::string>& levels);
+  std::vector<LevelData*> get_in_use_levels();
 
  private:
   struct Level {
@@ -70,6 +72,7 @@ class Loader {
   bool init_tie(Timer& timer, LevelData& data);
   bool init_tfrag(Timer& timer, LevelData& data);
   bool init_shrub(Timer& timer, LevelData& data);
+  bool init_collide(Timer& timer, LevelData& data);
 
   // used by game and loader thread
   std::unordered_map<std::string, Level> m_initializing_tfrag3_levels;
diff --git a/game/graphics/opengl_renderer/OpenGLRenderer.cpp b/game/graphics/opengl_renderer/OpenGLRenderer.cpp
index 7858b133e..c715169ee 100644
--- a/game/graphics/opengl_renderer/OpenGLRenderer.cpp
+++ b/game/graphics/opengl_renderer/OpenGLRenderer.cpp
@@ -55,7 +55,6 @@ OpenGLRenderer::OpenGLRenderer(std::shared_ptr<TexturePool> texture_pool,
                                std::shared_ptr<Loader> loader)
     : m_render_state(texture_pool, loader) {
   // setup OpenGL errors
-
   glEnable(GL_DEBUG_OUTPUT);
   glDebugMessageCallback(opengl_error_callback, nullptr);
   // disable specific errors
@@ -295,7 +294,6 @@ void OpenGLRenderer::render(DmaFollower dma, const RenderOptions& settings) {
   m_render_state.reset();
   m_render_state.ee_main_memory = g_ee_main_mem;
   m_render_state.offset_of_s7 = offset_of_s7();
-  m_render_state.has_camera_planes = false;
 
   {
     auto prof = m_profiler.root()->make_scoped_child("frame-setup");
@@ -368,6 +366,7 @@ void OpenGLRenderer::draw_renderer_selection_window() {
   ImGui::Begin("Renderer Debug");
 
   ImGui::Checkbox("Use old single-draw", &m_render_state.no_multidraw);
+  ImGui::Checkbox("Render collision mesh", &m_render_state.render_collision_mesh);
   ImGui::SliderFloat("Fog Adjust", &m_render_state.fog_intensity, 0, 10);
   ImGui::Checkbox("Sky CPU", &m_render_state.use_sky_cpu);
   ImGui::Checkbox("Occlusion Cull", &m_render_state.use_occlusion_culling);
@@ -458,6 +457,12 @@ void OpenGLRenderer::dispatch_buckets(DmaFollower dma, ScopedProfilerNode& prof)
     m_render_state.next_bucket += 16;
     vif_interrupt_callback();
     m_category_times[(int)m_bucket_categories[bucket_id]] += bucket_prof.get_elapsed_time();
+
+    // hack to draw the collision mesh in the middle the drawing
+    if (bucket_id == (int)BucketId::ALPHA_TEX_LEVEL0 - 1 && m_render_state.render_collision_mesh) {
+      auto p = prof.make_scoped_child("collision-draw");
+      m_collide_renderer.render(&m_render_state, p);
+    }
   }
   g_current_render = "";
 
diff --git a/game/graphics/opengl_renderer/OpenGLRenderer.h b/game/graphics/opengl_renderer/OpenGLRenderer.h
index bc2e5e98b..b73c28622 100644
--- a/game/graphics/opengl_renderer/OpenGLRenderer.h
+++ b/game/graphics/opengl_renderer/OpenGLRenderer.h
@@ -8,6 +8,7 @@
 #include "game/graphics/opengl_renderer/BucketRenderer.h"
 #include "game/graphics/opengl_renderer/Profiler.h"
 #include "game/graphics/opengl_renderer/opengl_utils.h"
+#include "game/graphics/opengl_renderer/CollideMeshRenderer.h"
 
 struct RenderOptions {
   int window_height_px = 0;
@@ -24,9 +25,19 @@ struct RenderOptions {
   float pmode_alp_register = 0.f;
 };
 
+/*!
+ * Main OpenGL renderer.
+ * This handles the glClear and all game rendering, but not actual setup, synchronization or imgui
+ * stuff.
+ *
+ * It is simply a collection of bucket renderers, and a few special case ones.
+ */
 class OpenGLRenderer {
  public:
   OpenGLRenderer(std::shared_ptr<TexturePool> texture_pool, std::shared_ptr<Loader> loader);
+
+  // rendering interface: takes the dma chain from the game, and some size/debug settings from
+  // the graphics system.
   void render(DmaFollower dma, const RenderOptions& settings);
 
  private:
@@ -58,6 +69,7 @@ class OpenGLRenderer {
 
   std::array<float, (int)BucketCategory::MAX_CATEGORIES> m_category_times;
   FullScreenDraw m_blackout_renderer;
+  CollideMeshRenderer m_collide_renderer;
 
   float m_last_pmode_alp = 1.;
   bool m_enable_fast_blackout_loads = true;
diff --git a/game/graphics/opengl_renderer/Shader.cpp b/game/graphics/opengl_renderer/Shader.cpp
index 022c23718..f92992d45 100644
--- a/game/graphics/opengl_renderer/Shader.cpp
+++ b/game/graphics/opengl_renderer/Shader.cpp
@@ -83,4 +83,9 @@ ShaderLibrary::ShaderLibrary() {
   at(ShaderId::OCEAN_COMMON) = {"ocean_common"};
   at(ShaderId::SHRUB) = {"shrub"};
   at(ShaderId::SHADOW) = {"shadow"};
+  at(ShaderId::COLLISION) = {"collision"};
+
+  for (auto& shader : m_shaders) {
+    ASSERT_MSG(shader.okay(), "Shader compiled");
+  }
 }
diff --git a/game/graphics/opengl_renderer/Shader.h b/game/graphics/opengl_renderer/Shader.h
index 52d013928..622aae73f 100644
--- a/game/graphics/opengl_renderer/Shader.h
+++ b/game/graphics/opengl_renderer/Shader.h
@@ -40,6 +40,7 @@ enum class ShaderId {
   OCEAN_COMMON = 15,
   SHADOW = 16,
   SHRUB = 17,
+  COLLISION = 18,
   MAX_SHADERS
 };
 
diff --git a/game/graphics/opengl_renderer/Sprite3.cpp b/game/graphics/opengl_renderer/Sprite3.cpp
index 0dd2fc466..0e41da2f1 100644
--- a/game/graphics/opengl_renderer/Sprite3.cpp
+++ b/game/graphics/opengl_renderer/Sprite3.cpp
@@ -649,7 +649,7 @@ void Sprite3::do_block_common(SpriteMode mode,
       flush_sprites(render_state, prof, mode == ModeHUD);
     }
 
-    if (mode == Mode2D && render_state->has_camera_planes && m_enable_culling) {
+    if (mode == Mode2D && render_state->has_pc_data && m_enable_culling) {
       // we can skip sprites that are out of view
       // it's probably possible to do this for 3D as well.
       auto bsphere = m_vec_data_2d[sprite_idx].xyz_sx;
diff --git a/game/graphics/opengl_renderer/SpriteRenderer.cpp b/game/graphics/opengl_renderer/SpriteRenderer.cpp
index 4e26d6951..0bbe697a6 100644
--- a/game/graphics/opengl_renderer/SpriteRenderer.cpp
+++ b/game/graphics/opengl_renderer/SpriteRenderer.cpp
@@ -653,7 +653,7 @@ void SpriteRenderer::do_block_common(SpriteMode mode,
       flush_sprites(render_state, prof);
     }
 
-    if (mode == Mode2D && render_state->has_camera_planes && m_enable_culling) {
+    if (mode == Mode2D && render_state->has_pc_data && m_enable_culling) {
       // we can skip sprites that are out of view
       // it's probably possible to do this for 3D as well.
       auto bsphere = m_vec_data_2d[sprite_idx].xyz_sx;
diff --git a/game/graphics/opengl_renderer/background/Shrub.cpp b/game/graphics/opengl_renderer/background/Shrub.cpp
index 38f5d06d4..980c30632 100644
--- a/game/graphics/opengl_renderer/background/Shrub.cpp
+++ b/game/graphics/opengl_renderer/background/Shrub.cpp
@@ -51,11 +51,11 @@ void Shrub::render(DmaFollower& dma, SharedRenderState* render_state, ScopedProf
         2 * (0xff & m_pc_port_data.itimes[i / 2].data()[2 * (i % 2)]) / 127.f;
   }
 
+  update_render_state_from_pc_settings(render_state, m_pc_port_data);
+
   for (int i = 0; i < 4; i++) {
     settings.planes[i] = m_pc_port_data.planes[i];
-    render_state->camera_planes[i] = m_pc_port_data.planes[i];
   }
-  render_state->has_camera_planes = true;
 
   m_has_level = setup_for_level(m_pc_port_data.level_name, render_state);
   render_all_trees(settings, render_state, prof);
diff --git a/game/graphics/opengl_renderer/background/TFragment.cpp b/game/graphics/opengl_renderer/background/TFragment.cpp
index d6833c1a9..20273b571 100644
--- a/game/graphics/opengl_renderer/background/TFragment.cpp
+++ b/game/graphics/opengl_renderer/background/TFragment.cpp
@@ -125,11 +125,11 @@ void TFragment::render(DmaFollower& dma,
       settings.occlusion_culling = render_state->occlusion_vis[m_level_id].data;
     }
 
+    update_render_state_from_pc_settings(render_state, m_pc_port_data);
+
     for (int i = 0; i < 4; i++) {
       settings.planes[i] = m_pc_port_data.planes[i];
-      render_state->camera_planes[i] = m_pc_port_data.planes[i];
     }
-    render_state->has_camera_planes = true;
 
     if (m_override_time_of_day) {
       for (int i = 0; i < 8; i++) {
diff --git a/game/graphics/opengl_renderer/background/Tie3.cpp b/game/graphics/opengl_renderer/background/Tie3.cpp
index 5590bf657..47d18b418 100644
--- a/game/graphics/opengl_renderer/background/Tie3.cpp
+++ b/game/graphics/opengl_renderer/background/Tie3.cpp
@@ -353,11 +353,11 @@ void Tie3::render(DmaFollower& dma, SharedRenderState* render_state, ScopedProfi
     settings.occlusion_culling = render_state->occlusion_vis[m_level_id].data;
   }
 
+  update_render_state_from_pc_settings(render_state, m_pc_port_data);
+
   for (int i = 0; i < 4; i++) {
     settings.planes[i] = m_pc_port_data.planes[i];
-    render_state->camera_planes[i] = m_pc_port_data.planes[i];
   }
-  render_state->has_camera_planes = true;
 
   if (false) {
     //    for (int i = 0; i < 8; i++) {
diff --git a/game/graphics/opengl_renderer/background/background_common.cpp b/game/graphics/opengl_renderer/background/background_common.cpp
index 7326d9863..343f3294c 100644
--- a/game/graphics/opengl_renderer/background/background_common.cpp
+++ b/game/graphics/opengl_renderer/background/background_common.cpp
@@ -658,4 +658,17 @@ u32 make_all_visible_index_list(std::pair<int, int>* group_out,
   }
   *num_tris_out = num_tris;
   return idx_buffer_ptr;
+}
+
+void update_render_state_from_pc_settings(SharedRenderState* state, const TfragPcPortData& data) {
+  if (!state->has_pc_data) {
+    for (int i = 0; i < 4; i++) {
+      state->camera_planes[i] = data.planes[i];
+      state->camera_matrix[i] = data.camera[i];
+    }
+    state->camera_pos = data.cam_trans;
+    state->camera_hvdf_off = data.hvdf_off;
+    state->camera_fog = data.fog;
+    state->has_pc_data = true;
+  }
 }
\ No newline at end of file
diff --git a/game/graphics/opengl_renderer/background/background_common.h b/game/graphics/opengl_renderer/background/background_common.h
index 908386dc3..d48a37a13 100644
--- a/game/graphics/opengl_renderer/background/background_common.h
+++ b/game/graphics/opengl_renderer/background/background_common.h
@@ -3,6 +3,19 @@
 #include "common/math/Vector.h"
 #include "game/graphics/opengl_renderer/BucketRenderer.h"
 
+// data passed from game to PC renderers
+// the GOAL code assumes this memory layout.
+struct TfragPcPortData {
+  math::Vector4f planes[4];
+  math::Vector<s32, 4> itimes[4];
+  math::Vector4f camera[4];
+  math::Vector4f hvdf_off;
+  math::Vector4f fog;
+  math::Vector4f cam_trans;
+  char level_name[16];
+};
+
+// inputs to background renderers.
 struct TfragRenderSettings {
   math::Matrix4f math_camera;
   math::Vector4f hvdf_offset;
@@ -12,7 +25,6 @@ struct TfragRenderSettings {
   math::Vector4f planes[4];
   bool debug_culling = false;
   const u8* occlusion_culling = nullptr;
-  // todo occlusion culling string.
 };
 
 enum class DoubleDrawKind { NONE, AFAIL_NO_DEPTH_WRITE };
@@ -50,15 +62,7 @@ void cull_check_all_slow(const math::Vector4f* planes,
                          u8* out);
 bool sphere_in_view_ref(const math::Vector4f& sphere, const math::Vector4f* planes);
 
-struct TfragPcPortData {
-  math::Vector4f planes[4];
-  math::Vector<s32, 4> itimes[4];
-  math::Vector4f camera[4];
-  math::Vector4f hvdf_off;
-  math::Vector4f fog;
-  char level_name[12];
-  u32 tree_idx;
-};
+void update_render_state_from_pc_settings(SharedRenderState* state, const TfragPcPortData& data);
 
 void make_all_visible_multidraws(std::pair<int, int>* draw_ptrs_out,
                                  GLsizei* counts_out,
diff --git a/game/graphics/opengl_renderer/shaders/collision.frag b/game/graphics/opengl_renderer/shaders/collision.frag
new file mode 100644
index 000000000..635a50c27
--- /dev/null
+++ b/game/graphics/opengl_renderer/shaders/collision.frag
@@ -0,0 +1,9 @@
+#version 430 core
+
+out vec4 color;
+
+in vec4 fragment_color;
+
+void main() {
+    color = fragment_color;
+}
diff --git a/game/graphics/opengl_renderer/shaders/collision.vert b/game/graphics/opengl_renderer/shaders/collision.vert
new file mode 100644
index 000000000..b95fc892f
--- /dev/null
+++ b/game/graphics/opengl_renderer/shaders/collision.vert
@@ -0,0 +1,67 @@
+#version 430 core
+
+layout (location = 0) in vec3 position_in;
+layout (location = 1) in uint flags;
+layout (location = 2) in vec3 normal_in;
+
+uniform vec4 hvdf_offset;
+uniform mat4 camera;
+uniform vec4 camera_position;
+uniform float fog_constant;
+uniform float fog_min;
+uniform float fog_max;
+uniform int mode;
+
+out vec4 fragment_color;
+
+void main() {
+    // Step 3, the camera transform
+    vec4 transformed = -camera[3].xyzw;
+    transformed += -camera[0] * position_in.x;
+    transformed += -camera[1] * position_in.y;
+    transformed += -camera[2] * position_in.z;
+
+    // compute Q
+    float Q = fog_constant / transformed[3];
+
+    // perspective divide!
+    transformed.xyz *= Q;
+
+    // offset
+    transformed.xyz += hvdf_offset.xyz;
+
+    // ftoi4
+    //transformed.xyzw *= 16;
+
+    // correct xy offset
+    transformed.xy -= (2048.);
+
+    // correct z scale
+    transformed.z /= (8388608);
+    transformed.z -= 1;
+
+    // correct xy scale
+    transformed.x /= (256);
+    transformed.y /= -(128);
+
+    // hack
+    transformed.xyz *= transformed.w;
+
+    gl_Position = transformed;
+    // scissoring area adjust
+    gl_Position.y *= 512.0/448.0;
+
+    vec3 to_cam = camera_position.xyz - position_in;
+    float dist_from_cam = length(to_cam);
+    vec3 to_cam_n = to_cam / dist_from_cam;
+    float cam_dot = abs(dot(to_cam_n, normal_in));
+
+    // color
+    if (mode == 0) {
+        fragment_color = vec4(0.4, 0.5, 0.5, 1);
+        fragment_color.xyz *= (pow(cam_dot, 3) + 0.3);
+    } else {
+        fragment_color = vec4(0.0, 0.3, 0.3, 1);
+    }
+
+}
diff --git a/goal_src/engine/gfx/tfrag/tfrag.gc b/goal_src/engine/gfx/tfrag/tfrag.gc
index 901602761..e44fbdea9 100644
--- a/goal_src/engine/gfx/tfrag/tfrag.gc
+++ b/goal_src/engine/gfx/tfrag/tfrag.gc
@@ -322,7 +322,7 @@
 (defun add-pc-tfrag3-data ((dma-buf dma-buffer) (lev level))
   "Add PC-port specific tfrag data"
   (let ((packet (the-as dma-packet (-> dma-buf base))))
-    (set! (-> packet dma) (new 'static 'dma-tag :id (dma-tag-id cnt) :qwc 15))
+    (set! (-> packet dma) (new 'static 'dma-tag :id (dma-tag-id cnt) :qwc 16))
     (set! (-> packet vif0) (new 'static 'vif-tag))
     (set! (-> packet vif1) (new 'static 'vif-tag :cmd (vif-cmd pc-port)))
     (set! (-> dma-buf base) (the pointer (&+ packet 16)))
@@ -348,9 +348,10 @@
       (set! (-> vec y) (-> *math-camera* fog-min))
       (set! (-> vec z) (-> *math-camera* fog-max))
       )
-    (charp<-string (the (pointer uint8) (&-> data-ptr 14)) (symbol->string (-> lev nickname)))
+    (set! (-> data-ptr 14) (-> (math-camera-pos) quad))
+    (charp<-string (the (pointer uint8) (&-> data-ptr 15)) (symbol->string (-> lev nickname)))
     )
-  (&+! (-> dma-buf base) (* 16 15))
+  (&+! (-> dma-buf base) (* 16 16))
   )
 
 ;;;;;;;;;;;;;;;;;;;;;