From 1254d93fbece019ba6952ff57642c818c2e3266d Mon Sep 17 00:00:00 2001
From: Hat Kid <6624576+Hat-Kid@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:39:21 +0200
Subject: [PATCH] custom levels: support custom regions in jak2/3 (#4300)

This adds support for generating pairs with `DataObjectGenerator` and
defining your own regions and `actor-group`s in custom levels.
---
 .../jak2/levels/test-zone/test-zone.jsonc     | 194 +++++++-
 .../jak3/levels/test-zone/test-zone.jsonc     | 194 +++++++-
 .../jak2/levels/test-zone/test-zone-obs.gc    |  34 +-
 .../jak3/levels/test-zone/test-zone-obs.gc    |  30 +-
 goalc/CMakeLists.txt                          |   2 +
 goalc/build_level/common/FileInfo.cpp         |  19 +-
 goalc/build_level/jak2/Entity.cpp             |  71 ++-
 goalc/build_level/jak2/Entity.h               |  17 +-
 goalc/build_level/jak2/LevelFile.cpp          |   7 +-
 goalc/build_level/jak2/LevelFile.h            |  17 +-
 goalc/build_level/jak2/Region.cpp             | 423 ++++++++++++++++++
 goalc/build_level/jak2/Region.h               | 207 +++++++++
 goalc/build_level/jak2/build_level.cpp        |  27 ++
 goalc/build_level/jak3/Entity.cpp             |  69 ++-
 goalc/build_level/jak3/Entity.h               |  17 +-
 goalc/build_level/jak3/LevelFile.cpp          |   6 +-
 goalc/build_level/jak3/LevelFile.h            |  16 +-
 goalc/build_level/jak3/Region.cpp             | 423 ++++++++++++++++++
 goalc/build_level/jak3/Region.h               | 207 +++++++++
 goalc/build_level/jak3/build_level.cpp        |  27 ++
 goalc/data_compiler/DataObjectGenerator.cpp   | 140 ++++++
 goalc/data_compiler/DataObjectGenerator.h     |  10 +
 22 files changed, 2111 insertions(+), 46 deletions(-)
 create mode 100644 goalc/build_level/jak2/Region.cpp
 create mode 100644 goalc/build_level/jak2/Region.h
 create mode 100644 goalc/build_level/jak3/Region.cpp
 create mode 100644 goalc/build_level/jak3/Region.h

diff --git a/custom_assets/jak2/levels/test-zone/test-zone.jsonc b/custom_assets/jak2/levels/test-zone/test-zone.jsonc
index 5953484bd8..7280e29e2e 100644
--- a/custom_assets/jak2/levels/test-zone/test-zone.jsonc
+++ b/custom_assets/jak2/levels/test-zone/test-zone.jsonc
@@ -53,9 +53,12 @@
   // The base actor id for your custom level. If you have multiple levels, this should be unique!
   "base_id": 100,
 
+  // Base id for regions.
+  "base_region_id": 0,
+
   // All art groups you want to use in your custom level. Will add their models and corresponding textures to the FR3 file.
   // Commented out so that the release builds don't have to double-decompile the game
-  // "art_groups": ["yakow-ag"],
+  // "art_groups": ["yakow-ag", "water-anim-fortress-ag"],
 
   // If you have any custom models in the "custom_assets/jak2/models/custom_levels" folder that you want to use in your level, add them to this list.
   // Note: Like with art groups, these should also be added to your level's .gd file.
@@ -69,6 +72,177 @@
   // If you want all textures from a tpage, you can just do ["tpage-name"].
   "textures": ["yak-medfur-end"], // for yakow texture fix
 
+  // Any regions you want to include in your custom level.
+  // Regions run scripts that do things like loading specific levels,
+  // playing ambient sounds, checking if a task is completed in order to e.g. open airlocks, play cutscenes, etc.
+  //
+  // They can have three scripts that run on different conditions:
+  // - A single time when entering the region's bounds (on-enter)
+  // - Once every frame while you are inside a region (on-inside)
+  // - A single time when exiting a region's bounds (on-exit)
+  // Scripts are Lisp pairs, e.g. (want-load 'ctysluma 'ctyindb 'ctywide).
+  // The list of commands that can be used is too exhaustive to show here and there is no proper documentation for this,
+  // but you can refer to https://github.com/open-goal/jak-project/blob/master/goal_src/jak2/engine/util/script.gc
+  // for more information or inspect other regions via the debug menu in-game for examples.
+  //
+  // There are two special cases for script forms: "entity-actor" and "actor-group".
+  // Region scripts can refer to entities or actor groups that are stored inside the level data,
+  // so forms that start with either of these will be changed during the level building process to insert a reference
+  // to the given object.
+  //
+  // Regions can either be spheres, planes or volumes.
+  // Spheres do not need anything special, just the trans and bsphere, but if you want a face or a volume,
+  // you need to additionally specify a "face" or a "volume" key.
+  // A "face" key contains the face normal and a list of points.
+  // A "volume" key contains a list of faces.
+  //
+  // There are different types of regions like ones that get triggered based on camera position, Jak's position, etc.
+  // Each type of region is stored in its own region tree, each of which has its own bsphere that all its regions must be encompassed within.
+  // The full list is as follows:
+  // target (Jak based), camera (camera based), data (?), water (water volumes), city_vis (?),
+  // sample (?), light (presumably for foreground lights), entity (?)
+  "region_trees": {
+    // camera regions are activated when the camera enters their bounds
+    "camera": {
+      // every region tree has its own bsphere. all of a tree's regions must be encompassed within this sphere.
+      "bsphere": [0, 0, 0, 50],
+      "regions": [
+        {
+          "id": 1,
+          "shape": "sphere", // can be "sphere", "face" or "volume"
+          "trans": [-17, 4, 30],
+          "bsphere": [-17, 4, 30, 5],
+          // "(actor-group 2)" will be replaced with an actual reference
+          // to the actor-group in the level data with id 2.
+          "on-enter": "(begin (print 'enter1) (send-event (actor-group 2) 'none))",
+          "on-inside": "(begin (sound-play-loop \"punch\") (sound-play-loop \"spin\"))",
+          "on-exit": "(print 'exit1)"
+        }
+      ]
+    },
+    // target regions are activated when Jak enters their bounds
+    "target": {
+      "bsphere": [0, 0, 0, 50],
+      "regions": [
+        {
+          "id": 2,
+          "shape": "face",
+          "on-enter": "(begin (print 'enter14) (send-event \"test-actor\" 'rot))",
+          "bsphere": [3.37, 6.2, 16.59, 7.0711],
+          "face": {
+            "normal": [-0.615662, 0.0, -0.788011, -15.147877],
+            "points": [
+              [-0.570054, 0, 19.668308],
+              [-0.570053, 11, 19.668308],
+              [7.310053, 0, 13.511692],
+              [7.310053, 11, 13.511692]
+            ]
+          }
+        }
+      ]
+    },
+    // water regions are used to define water volumes
+    "water": {
+      "bsphere": [0, 0, 0, 200],
+      "regions": [
+        {
+          "id": 3,
+          "shape": "sphere",
+          // "(entity-actor water-anim-test-zone-1)" will be replaced with an actual reference of the entity with that name.
+          "on-inside": "(water water-anim (entity-actor water-anim-test-zone-1) (swim wade))",
+          "trans": [5.0, 6.0, -66.0],
+          "bsphere": [5.0, 6.0, -66.0, 50.0]
+        },
+        {
+          "id": 4,
+          "shape": "volume",
+          "on-inside": "(water height 0.0 (swim wade))",
+          "bsphere": [5.1664, 9.4453, 51.2316, 25.2828],
+          "volume": {
+            "faces": [
+              {
+                "normal": [-1.0, 0.0, 0.0, 11.785238],
+                "points": [
+                  [-11.785238, -2.468076, 65.720734],
+                  [-11.785238, 21.358631, 65.720734],
+                  [-11.785238, -2.468076, 36.742477],
+                  [-11.785238, 21.358631, 36.742477]
+                ]
+              },
+              {
+                "normal": [0.0, 0.0, -1.0, -36.742475],
+                "points": [
+                  [-11.785238, -2.468076, 36.742477],
+                  [-11.785238, 21.358631, 36.742477],
+                  [22.118128, -2.468076, 36.742477],
+                  [22.118128, 21.358631, 36.742477]
+                ]
+              },
+              {
+                "normal": [1.0, 0.0, 0.0, 22.118128],
+                "points": [
+                  [22.118128, -2.468076, 36.742477],
+                  [22.118128, 21.358631, 36.742477],
+                  [22.118128, -2.468076, 65.720734],
+                  [22.118128, 21.358631, 65.720734]
+                ]
+              },
+              {
+                "normal": [0.0, 0.0, 1.0, 65.72073],
+                "points": [
+                  [22.118128, -2.468076, 65.720734],
+                  [22.118128, 21.358631, 65.720734],
+                  [-11.785238, -2.468076, 65.720734],
+                  [-11.785238, 21.358631, 65.720734]
+                ]
+              },
+              {
+                "normal": [0.0, -1.0, 0.0, 2.468076],
+                "points": [
+                  [-11.785238, -2.468076, 36.742477],
+                  [22.118128, -2.468076, 36.742477],
+                  [-11.785238, -2.468076, 65.720734],
+                  [22.118128, -2.468076, 65.720734]
+                ]
+              },
+              {
+                "normal": [0.0, 1.0, 0.0, 21.358631],
+                "points": [
+                  [22.118128, 21.358631, 36.742477],
+                  [-11.785238, 21.358631, 36.742477],
+                  [22.118128, 21.358631, 65.720734],
+                  [-11.785238, 21.358631, 65.720734]
+                ]
+              }
+            ]
+          }
+        }
+      ]
+    },
+    "data": {},
+    "city_vis": {},
+    "sample": {},
+    "light": {},
+    "entity": {}
+  },
+
+  // Actor groups you want to include in your level.
+  //
+  // Actor groups are arrays of entities, used for example in regions to send events to a list of actors
+  // or in "battles" as a list of enemies that need to be defeated before being able to progress.
+  // You can give them an id, this has no effect in-game, but it is used for region scripts so the level builder
+  // knows which actor group to insert.
+  "actor_groups": [
+    {
+      "id": 0,
+      "entities": ["test-crate", "test-eco", "test-yakow"]
+    },
+    {
+      "id": 2,
+      "entities": ["test-crate", "test-actor"]
+    }
+  ],
+
   "actors": [
     {
       "trans": [-15.2818, 15.2461, 17.136], // translation
@@ -115,6 +289,24 @@
       "lump": {
         "name": "test-actor"
       }
+    },
+    {
+      "trans": [5, 6.778769493103027, -66],
+      "etype": "water-anim-test-zone",
+      "game_task": 0,
+      "quat": [0.0, 0.0, 0.0, 1.0],
+      "bsphere": [5, 6.778769493103027, -66, 50],
+      "lump": {
+        "look": ["int32", 21],
+        "name": "water-anim-test-zone-1",
+        "water-height": [
+          "water-height",
+          6.77869987487793,
+          0.5,
+          2.0,
+          "(water-flags can-swim can-wade)"
+        ]
+      }
     }
   ]
 }
diff --git a/custom_assets/jak3/levels/test-zone/test-zone.jsonc b/custom_assets/jak3/levels/test-zone/test-zone.jsonc
index af145a51b1..04c969423c 100644
--- a/custom_assets/jak3/levels/test-zone/test-zone.jsonc
+++ b/custom_assets/jak3/levels/test-zone/test-zone.jsonc
@@ -53,9 +53,12 @@
   // The base actor id for your custom level. If you have multiple levels, this should be unique!
   "base_id": 100,
 
+  // Base id for regions.
+  "base_region_id": 0,
+
   // All art groups you want to use in your custom level. Will add their models and corresponding textures to the FR3 file.
   // Commented out so that the release builds don't have to double-decompile the game
-  // "art_groups": ["yakow-ag"],
+  // "art_groups": ["yakow-ag", "water-anim-waspala-ag"],
 
   // If you have any custom models in the "custom_assets/jak3/models/custom_levels" folder that you want to use in your level, add them to this list.
   // Note: Like with art groups, these should also be added to your level's .gd file.
@@ -69,6 +72,177 @@
   // If you want all textures from a tpage, you can just do ["tpage-name"].
   "textures": ["yak-medfur-end"], // for yakow texture fix
 
+  // Any regions you want to include in your custom level.
+  // Regions run scripts that do things like loading specific levels,
+  // playing ambient sounds, checking if a task is completed in order to e.g. open airlocks, play cutscenes, etc.
+  //
+  // They can have three scripts that run on different conditions:
+  // - A single time when entering the region's bounds (on-enter)
+  // - Once every frame while you are inside a region (on-inside)
+  // - A single time when exiting a region's bounds (on-exit)
+  // Scripts are Lisp pairs, e.g. (want-load 'ctysluma 'ctyindb 'ctywide).
+  // The list of commands that can be used is too exhaustive to show here and there is no proper documentation for this,
+  // but you can refer to https://github.com/open-goal/jak-project/blob/master/goal_src/jak3/engine/util/script.gc
+  // for more information or inspect other regions via the debug menu in-game for examples.
+  //
+  // There are two special cases for script forms: "entity-actor" and "actor-group".
+  // Region scripts can refer to entities or actor groups that are stored inside the level data,
+  // so forms that start with either of these will be changed during the level building process to insert a reference
+  // to the given object.
+  //
+  // Regions can either be spheres, planes or volumes.
+  // Spheres do not need anything special, just the trans and bsphere, but if you want a face or a volume,
+  // you need to additionally specify a "face" or a "volume" key.
+  // A "face" key contains the face normal and a list of points.
+  // A "volume" key contains a list of faces.
+  //
+  // There are different types of regions like ones that get triggered based on camera position, Jak's position, etc.
+  // Each type of region is stored in its own region tree, each of which has its own bsphere that all its regions must be encompassed within.
+  // The full list is as follows:
+  // target (Jak based), camera (camera based), data (?), water (water volumes), city_vis (?),
+  // sample (?), light (presumably for foreground lights), entity (?)
+  "region_trees": {
+    // camera regions are activated when the camera enters their bounds
+    "camera": {
+      // every region tree has its own bsphere. all of a tree's regions must be encompassed within this sphere.
+      "bsphere": [0, 0, 0, 50],
+      "regions": [
+        {
+          "id": 1,
+          "shape": "sphere", // can be "sphere", "face" or "volume"
+          "trans": [-17, 4, 30],
+          "bsphere": [-17, 4, 30, 5],
+          // "(actor-group 2)" will be replaced with an actual reference
+          // to the actor-group in the level data with id 2.
+          "on-enter": "(begin (print 'enter1) (send-event (actor-group 2) 'none))",
+          "on-inside": "(begin (sound-play-loop \"punch\") (sound-play-loop \"spin\"))",
+          "on-exit": "(print 'exit1)"
+        }
+      ]
+    },
+    // target regions are activated when Jak enters their bounds
+    "target": {
+      "bsphere": [0, 0, 0, 50],
+      "regions": [
+        {
+          "id": 2,
+          "shape": "face",
+          "on-enter": "(begin (print 'enter14) (send-event \"test-actor\" 'rot))",
+          "bsphere": [3.37, 6.2, 16.59, 7.0711],
+          "face": {
+            "normal": [-0.615662, 0.0, -0.788011, -15.147877],
+            "points": [
+              [-0.570054, 0, 19.668308],
+              [-0.570053, 11, 19.668308],
+              [7.310053, 0, 13.511692],
+              [7.310053, 11, 13.511692]
+            ]
+          }
+        }
+      ]
+    },
+    // water regions are used to define water volumes
+    "water": {
+      "bsphere": [0, 0, 0, 200],
+      "regions": [
+        {
+          "id": 3,
+          "shape": "sphere",
+          // "(entity-actor water-anim-test-zone-1)" will be replaced with an actual reference of the entity with that name.
+          "on-inside": "(water water-anim (entity-actor water-anim-test-zone-1) (swim wade))",
+          "trans": [5.0, 6.0, -66.0],
+          "bsphere": [5.0, 6.0, -66.0, 50.0]
+        },
+        {
+          "id": 4,
+          "shape": "volume",
+          "on-inside": "(water height 0.0 (swim wade))",
+          "bsphere": [5.1664, 9.4453, 51.2316, 25.2828],
+          "volume": {
+            "faces": [
+              {
+                "normal": [-1.0, 0.0, 0.0, 11.785238],
+                "points": [
+                  [-11.785238, -2.468076, 65.720734],
+                  [-11.785238, 21.358631, 65.720734],
+                  [-11.785238, -2.468076, 36.742477],
+                  [-11.785238, 21.358631, 36.742477]
+                ]
+              },
+              {
+                "normal": [0.0, 0.0, -1.0, -36.742475],
+                "points": [
+                  [-11.785238, -2.468076, 36.742477],
+                  [-11.785238, 21.358631, 36.742477],
+                  [22.118128, -2.468076, 36.742477],
+                  [22.118128, 21.358631, 36.742477]
+                ]
+              },
+              {
+                "normal": [1.0, 0.0, 0.0, 22.118128],
+                "points": [
+                  [22.118128, -2.468076, 36.742477],
+                  [22.118128, 21.358631, 36.742477],
+                  [22.118128, -2.468076, 65.720734],
+                  [22.118128, 21.358631, 65.720734]
+                ]
+              },
+              {
+                "normal": [0.0, 0.0, 1.0, 65.72073],
+                "points": [
+                  [22.118128, -2.468076, 65.720734],
+                  [22.118128, 21.358631, 65.720734],
+                  [-11.785238, -2.468076, 65.720734],
+                  [-11.785238, 21.358631, 65.720734]
+                ]
+              },
+              {
+                "normal": [0.0, -1.0, 0.0, 2.468076],
+                "points": [
+                  [-11.785238, -2.468076, 36.742477],
+                  [22.118128, -2.468076, 36.742477],
+                  [-11.785238, -2.468076, 65.720734],
+                  [22.118128, -2.468076, 65.720734]
+                ]
+              },
+              {
+                "normal": [0.0, 1.0, 0.0, 21.358631],
+                "points": [
+                  [22.118128, 21.358631, 36.742477],
+                  [-11.785238, 21.358631, 36.742477],
+                  [22.118128, 21.358631, 65.720734],
+                  [-11.785238, 21.358631, 65.720734]
+                ]
+              }
+            ]
+          }
+        }
+      ]
+    },
+    "data": {},
+    "city_vis": {},
+    "sample": {},
+    "light": {},
+    "entity": {}
+  },
+
+  // Actor groups you want to include in your level.
+  //
+  // Actor groups are arrays of entities, used for example in regions to send events to a list of actors
+  // or in "battles" as a list of enemies that need to be defeated before being able to progress.
+  // You can give them an id, this has no effect in-game, but it is used for region scripts so the level builder
+  // knows which actor group to insert.
+  "actor_groups": [
+    {
+      "id": 0,
+      "entities": ["test-crate", "test-eco", "test-yakow"]
+    },
+    {
+      "id": 2,
+      "entities": ["test-crate", "test-actor"]
+    }
+  ],
+
   "actors": [
     {
       "trans": [-15.2818, 15.2461, 17.136], // translation
@@ -116,6 +290,24 @@
       "lump": {
         "name": "test-actor"
       }
+    },
+    {
+      "trans": [5, 6.778769493103027, -66],
+      "etype": "water-anim-test-zone",
+      "game_task": 0,
+      "quat": [0.0, 0.0, 0.0, 1.0],
+      "bsphere": [5, 6.778769493103027, -66, 50],
+      "lump": {
+        "look": ["int32", 7],
+        "name": "water-anim-test-zone-1",
+        "water-height": [
+          "water-height",
+          6.77869987487793,
+          0.5,
+          2.0,
+          "(water-flag can-swim can-wade)"
+        ]
+      }
     }
   ]
 }
diff --git a/goal_src/jak2/levels/test-zone/test-zone-obs.gc b/goal_src/jak2/levels/test-zone/test-zone-obs.gc
index 8729fbd32b..a4510585df 100644
--- a/goal_src/jak2/levels/test-zone/test-zone-obs.gc
+++ b/goal_src/jak2/levels/test-zone/test-zone-obs.gc
@@ -6,7 +6,8 @@
    (base       vector :inline)
    (old-base   vector :inline)
    (bob-offset int64)
-   (bob-amount float))
+   (bob-amount float)
+   (last-fast-rot time-frame))
   (:methods
    (init-collision! (_type_) object))
   (:state-methods
@@ -74,6 +75,7 @@
   :event
     (behavior ((proc process) (argc int) (message symbol) (block event-message-block))
       (case message
+        (('rot) (set-time! (-> self last-fast-rot)))
         (('attack 'touch)
          ; (if (= (-> proc type) target)
          ;   (send-event proc 'attack #f (static-attack-info ((shove-up (meters 2.5)) (shove-back (meters 7.5)))))
@@ -82,7 +84,7 @@
   :code
     (behavior ()
       (loop
-        (quaternion-rotate-y! (-> self root quat) (-> self root quat) (* (degrees 45) (seconds-per-frame)))
+        (quaternion-rotate-y! (-> self root quat) (-> self root quat) (* (degrees (if (not (time-elapsed? (-> self last-fast-rot) (seconds 2))) 240 45)) (seconds-per-frame)))
         (let ((bob (-> self bob-amount)))
           (when (< 0.0 bob)
             (set! (-> self root trans y)
@@ -99,3 +101,31 @@
         ;   )
         (suspend)))
   :post transform-post)
+
+(deftype water-anim-test-zone (water-anim)
+  ()
+  )
+
+(define ripple-for-water-anim-test-zone (new 'static 'ripple-wave-set
+                                         :count 3
+                                         :converted #f
+                                         :normal-scale 1.0
+                                         :wave (new 'static 'inline-array ripple-wave 4
+                                           (new 'static 'ripple-wave :scale 40.0 :xdiv 1 :speed 1.5)
+                                           (new 'static 'ripple-wave :scale 40.0 :xdiv -1 :zdiv 1 :speed 1.5)
+                                           (new 'static 'ripple-wave :scale 20.0 :xdiv 5 :zdiv 3 :speed 0.75)
+                                           (new 'static 'ripple-wave)
+                                           )
+                                         )
+        )
+
+(defmethod init-water! ((this water-anim-test-zone))
+  (call-parent-method this)
+  (set! (-> this draw ripple) (new 'process 'ripple-control))
+  (set-vector! (-> this draw color-mult) 0.01 0.45 0.5 0.75)
+  (set! (-> this draw ripple global-scale) (meters 0.75))
+  (set! (-> this draw ripple close-fade-dist) (meters 40))
+  (set! (-> this draw ripple far-fade-dist) (meters 60))
+  (set! (-> this draw ripple waveform) ripple-for-water-anim-test-zone)
+  (none)
+  )
\ No newline at end of file
diff --git a/goal_src/jak3/levels/test-zone/test-zone-obs.gc b/goal_src/jak3/levels/test-zone/test-zone-obs.gc
index 0443f60718..39906295d6 100644
--- a/goal_src/jak3/levels/test-zone/test-zone-obs.gc
+++ b/goal_src/jak3/levels/test-zone/test-zone-obs.gc
@@ -6,7 +6,8 @@
    (base       vector :inline)
    (old-base   vector :inline)
    (bob-offset int64)
-   (bob-amount float))
+   (bob-amount float)
+   (last-fast-rot time-frame))
   (:methods
    (init-collision! (_type_) object))
   (:state-methods
@@ -73,6 +74,7 @@
   :event
     (behavior ((proc process) (argc int) (message symbol) (block event-message-block))
       (case message
+        (('rot) (set-time! (-> self last-fast-rot)))
         (('attack 'touch)
          ; (if (= (-> proc type) target)
          ;   (send-event proc 'attack #f (static-attack-info ((shove-up (meters 2.5)) (shove-back (meters 7.5)))))
@@ -81,7 +83,7 @@
   :code
     (behavior ()
       (loop
-        (quaternion-rotate-y! (-> self root quat) (-> self root quat) (* (degrees 45) (seconds-per-frame)))
+        (quaternion-rotate-y! (-> self root quat) (-> self root quat) (* (degrees (if (not (time-elapsed? (-> self last-fast-rot) (seconds 2))) 240 45)) (seconds-per-frame)))
         (let ((bob (-> self bob-amount)))
           (when (< 0.0 bob)
             (set! (-> self root trans y)
@@ -98,3 +100,27 @@
         ;   )
         (suspend)))
   :post transform-post)
+
+(deftype water-anim-test-zone (water-anim) ())
+
+(define ripple-for-water-anim-test-zone (new 'static 'ripple-wave-set
+                                        :count 3
+                                        :converted #f
+                                        :normal-scale 1.0
+                                        :wave (new 'static 'inline-array ripple-wave 4
+                                          (new 'static 'ripple-wave :scale 10.0 :xdiv 1 :speed 1.5)
+                                          (new 'static 'ripple-wave :scale 10.0 :xdiv -1 :zdiv 1 :speed 1.5)
+                                          (new 'static 'ripple-wave :scale 5.0 :xdiv 5 :zdiv 3 :speed 0.75)
+                                          (new 'static 'ripple-wave)
+                                          )
+                                        )
+        )
+
+(defmethod init-water! ((this water-anim-test-zone))
+  (call-parent-method this)
+  (set! (-> this draw ripple) (new 'process 'ripple-control))
+  (set! (-> this draw ripple global-scale) (meters 0.75))
+  (set! (-> this draw ripple close-fade-dist) (meters 40))
+  (set! (-> this draw ripple far-fade-dist) (meters 60))
+  (set! (-> this draw ripple waveform) ripple-for-water-anim-test-zone)
+  )
\ No newline at end of file
diff --git a/goalc/CMakeLists.txt b/goalc/CMakeLists.txt
index 89b5d8a96c..3796f14026 100644
--- a/goalc/CMakeLists.txt
+++ b/goalc/CMakeLists.txt
@@ -36,6 +36,8 @@ add_library(compiler
         build_level/common/Tfrag.cpp
         build_level/common/Tie.cpp
         build_level/jak1/ambient.cpp
+        build_level/jak2/Region.cpp
+        build_level/jak3/Region.cpp
         compiler/Compiler.cpp
         compiler/Env.cpp
         compiler/Val.cpp
diff --git a/goalc/build_level/common/FileInfo.cpp b/goalc/build_level/common/FileInfo.cpp
index 34fb3c4972..2aa38da677 100644
--- a/goalc/build_level/common/FileInfo.cpp
+++ b/goalc/build_level/common/FileInfo.cpp
@@ -1,8 +1,23 @@
 #include "FileInfo.h"
 
+#include <chrono>
+
 #include "common/versions/versions.h"
 
 #include "goalc/data_compiler/DataObjectGenerator.h"
+#include <fmt/chrono.h>
+
+std::string get_current_time_and_date() {
+  auto const now = std::chrono::floor<std::chrono::seconds>(std::chrono::system_clock::now());
+  std::time_t const t = std::chrono::system_clock::to_time_t(now);
+  std::tm tm{};
+#if defined(_WIN32)
+  localtime_s(&tm, &t);
+#else
+  localtime_r(&t, &tm);
+#endif
+  return fmt::format("{:%a %b %d %H:%M:%S %Y}", tm);
+}
 
 size_t FileInfo::add_to_object_file(DataObjectGenerator& gen) const {
   gen.align_to_basic();
@@ -13,8 +28,8 @@ size_t FileInfo::add_to_object_file(DataObjectGenerator& gen) const {
   gen.add_word(major_version);
   gen.add_word(minor_version);
   gen.add_ref_to_string_in_pool(maya_file_name);
-  gen.add_ref_to_string_in_pool(tool_debug);
-  gen.add_ref_to_string_in_pool(tool_debug);
+  gen.add_ref_to_string_in_pool(tool_debug + " " + get_current_time_and_date() + "\n");
+  gen.add_ref_to_string_in_pool(mdb_file_name);
 
   return offset;
 }
diff --git a/goalc/build_level/jak2/Entity.cpp b/goalc/build_level/jak2/Entity.cpp
index 3eb1739002..c21df3c033 100644
--- a/goalc/build_level/jak2/Entity.cpp
+++ b/goalc/build_level/jak2/Entity.cpp
@@ -1,5 +1,7 @@
 #include "Entity.h"
 
+#include "common/util/Assert.h"
+
 namespace jak2 {
 size_t EntityActor::generate(DataObjectGenerator& gen) const {
   size_t result = res_lump.generate_header(gen, "entity-actor");
@@ -39,8 +41,7 @@ size_t generate_drawable_actor(DataObjectGenerator& gen,
   return result;
 }
 
-size_t generate_inline_array_actors(DataObjectGenerator& gen,
-                                    const std::vector<EntityActor>& actors) {
+size_t generate_inline_array_actors(DataObjectGenerator& gen, std::vector<EntityActor>& actors) {
   std::vector<size_t> actor_locs;
   for (auto& actor : actors) {
     actor_locs.push_back(actor.generate(gen));
@@ -62,6 +63,7 @@ size_t generate_inline_array_actors(DataObjectGenerator& gen,
   ASSERT((gen.current_offset_bytes() % 16) == 0);
 
   for (size_t i = 0; i < actors.size(); i++) {
+    actors[i].slot = actor_locs[i];
     generate_drawable_actor(gen, actors[i], actor_locs[i]);
   }
   return result;
@@ -94,10 +96,13 @@ void add_actors_from_json(const nlohmann::json& json,
     actor.bsphere = vectorm4_from_json(actor_json.at("bsphere"));
 
     if (actor_json.find("lump") != actor_json.end()) {
-      for (auto [key, value] : actor_json.at("lump").items()) {
+      for (auto& [key, value] : actor_json.at("lump").items()) {
         if (value.is_string()) {
           std::string value_string = value.get<std::string>();
-          if (value_string.size() > 0 && value_string[0] == '\'') {
+          if (key == "name") {
+            actor.name = value_string;
+          }
+          if (!value_string.empty() && value_string[0] == '\'') {
             actor.res_lump.add_res(
                 std::make_unique<ResSymbol>(key, value_string.substr(1), -1000000000.0000));
           } else {
@@ -115,4 +120,62 @@ void add_actors_from_json(const nlohmann::json& json,
     actor.res_lump.sort_res();
   }
 }
+
+size_t generate_actor_group(DataObjectGenerator& gen, const ActorGroup& group) {
+  gen.align_to_basic();
+  gen.add_type_tag("actor-group");
+  size_t result = gen.current_offset_bytes();
+  auto length = group.actors.size();
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_type_tag("entity-actor");
+  for (auto& actor : group.actors) {
+    gen.link_word_to_byte(gen.add_word(0), actor->slot);
+    gen.add_word(actor->aid);
+  }
+  gen.align(4);
+  return result;
+}
+
+size_t generate_actor_group_array(DataObjectGenerator& gen, std::vector<ActorGroup>& actor_groups) {
+  gen.align_to_basic();
+  gen.add_type_tag("array");
+  size_t result = gen.current_offset_bytes();
+  auto length = actor_groups.size();
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_type_tag("actor-group");
+  std::vector<size_t> group_slots;
+  for (auto& group : actor_groups) {
+    group_slots.push_back(gen.add_word(0));
+  }
+  gen.align(4);
+  for (int i = 0; i < group_slots.size(); i++) {
+    actor_groups.at(i).slot = generate_actor_group(gen, actor_groups.at(i));
+    gen.link_word_to_byte(group_slots.at(i), actor_groups.at(i).slot);
+  }
+
+  return result;
+}
+
+void add_actor_groups_from_json(const nlohmann::json& json,
+                                const std::vector<EntityActor>& actors,
+                                std::vector<ActorGroup>& actor_groups,
+                                u32 base_id) {
+  for (const auto& actor_group : json) {
+    auto& group = actor_groups.emplace_back();
+    group.id = actor_group.value("id", base_id + actor_groups.size());
+    auto entity_list = actor_group.value<std::vector<std::string>>("entities", {});
+    for (auto& ent_name : entity_list) {
+      auto ent = std::ranges::find_if(
+          actors, [ent_name](const EntityActor& actor) { return actor.name == ent_name; });
+      if (ent != actors.end()) {
+        group.actors.push_back(&*ent);
+      } else {
+        ASSERT_MSG(false, fmt::format("Failed to find actor \"{}\", declared in actor group id {}.",
+                                      ent_name, group.id));
+      }
+    }
+  }
+}
 }  // namespace jak2
diff --git a/goalc/build_level/jak2/Entity.h b/goalc/build_level/jak2/Entity.h
index d26678c143..c1aa76d7f0 100644
--- a/goalc/build_level/jak2/Entity.h
+++ b/goalc/build_level/jak2/Entity.h
@@ -13,6 +13,7 @@ namespace jak2 {
  *  (quat quaternion :inline :offset-assert 64)
  */
 struct EntityActor {
+  std::string name;
   ResLump res_lump;
   math::Vector4f trans;  // w = 1 here
   u32 aid = 0;
@@ -24,14 +25,26 @@ struct EntityActor {
 
   math::Vector4f bsphere;
 
+  size_t slot;
+
   size_t generate(DataObjectGenerator& gen) const;
 };
 
-size_t generate_inline_array_actors(DataObjectGenerator& gen,
-                                    const std::vector<EntityActor>& actors);
+struct ActorGroup {
+  u64 id;
+  std::vector<const EntityActor*> actors;
+  size_t slot;
+};
+
+size_t generate_inline_array_actors(DataObjectGenerator& gen, std::vector<EntityActor>& actors);
+size_t generate_actor_group_array(DataObjectGenerator& gen, std::vector<ActorGroup>& actor_groups);
 
 void add_actors_from_json(const nlohmann::json& json,
                           std::vector<EntityActor>& actor_list,
                           u32 base_aid,
                           decompiler::DecompilerTypeSystem& dts);
+void add_actor_groups_from_json(const nlohmann::json& json,
+                                const std::vector<EntityActor>& actors,
+                                std::vector<ActorGroup>& actor_groups,
+                                u32 base_id);
 }  // namespace jak2
\ No newline at end of file
diff --git a/goalc/build_level/jak2/LevelFile.cpp b/goalc/build_level/jak2/LevelFile.cpp
index 1741ea34d9..610b6907af 100644
--- a/goalc/build_level/jak2/LevelFile.cpp
+++ b/goalc/build_level/jak2/LevelFile.cpp
@@ -66,7 +66,7 @@ size_t generate_u32_array(const std::vector<u32>& array, DataObjectGenerator& ge
   return result;
 }
 
-std::vector<u8> LevelFile::save_object_file() const {
+std::vector<u8> LevelFile::save_object_file() {
   DataObjectGenerator gen;
   gen.add_type_tag("bsp-header");
 
@@ -78,7 +78,6 @@ std::vector<u8> LevelFile::save_object_file() const {
   //(info                   file-info                        :offset          4)
   auto file_info_slot = info.add_to_object_file(gen);
   gen.link_word_to_byte(1, file_info_slot);
-
   //(bsphere                vector :inline                   :offset-assert  16)
   //(all-visible-list       (pointer uint16)                 :offset-assert  32)
   //(visible-list-length    int32                            :offset-assert  36)
@@ -114,8 +113,12 @@ std::vector<u8> LevelFile::save_object_file() const {
   //(light-hash             light-hash                       :offset-assert 176)
   //(nav-meshes             (array entity-nav-mesh)          :offset-assert 180)
   //(actor-groups           (array actor-group)              :offset-assert 184)
+  gen.link_word_to_byte(184 / 4, generate_actor_group_array(gen, actor_groups));
   //(region-trees           (array drawable-tree-region-prim) :offset-assert 188)
+  gen.link_word_to_byte(188 / 4,
+                        generate_drawable_tree_region_prim_array(gen, region_array, region_trees));
   //(region-array           region-array                     :offset-assert 192)
+  gen.link_word_to_byte(192 / 4, region_array.slot);
   //(collide-hash           collide-hash                     :offset-assert 196)
   gen.link_word_to_byte(196 / 4, add_to_object_file(collide_hash, gen));
   //(wind-array             uint32                           :offset        200)
diff --git a/goalc/build_level/jak2/LevelFile.h b/goalc/build_level/jak2/LevelFile.h
index 611f2f4fef..cde320b918 100644
--- a/goalc/build_level/jak2/LevelFile.h
+++ b/goalc/build_level/jak2/LevelFile.h
@@ -12,6 +12,7 @@
 #include "goalc/build_level/common/Tie.h"
 #include "goalc/build_level/jak2/Entity.h"
 #include "goalc/build_level/jak2/FileInfo.h"
+#include "goalc/build_level/jak2/Region.h"
 
 namespace jak2 {
 struct VisibilityString {
@@ -22,13 +23,10 @@ struct DrawableTreeActor {};
 
 struct DrawableTreeInstanceShrub {};
 
-struct DrawableTreeRegionPrim {};
-
 struct DrawableTreeArray {
   std::vector<DrawableTreeTfrag> tfrags;
   std::vector<DrawableTreeInstanceTie> ties;
   std::vector<DrawableTreeActor> actors;  // unused?
-  std::vector<DrawableTreeRegionPrim> regions;
   std::vector<DrawableTreeInstanceShrub> shrubs;
   size_t add_to_object_file(DataObjectGenerator& gen) const;
 };
@@ -49,12 +47,6 @@ struct LightHash {};
 
 struct EntityNavMesh {};
 
-struct ActorGroup {};
-
-struct RegionTree {};
-
-struct RegionArray {};
-
 struct CityLevelInfo {};
 
 struct TextureMasksArray {};
@@ -141,7 +133,8 @@ struct LevelFile {
   //  (actor-groups           (array actor-group)              :offset-assert 184)
   std::vector<ActorGroup> actor_groups;
   //  (region-trees           (array drawable-tree-region-prim) :offset-assert 188)
-  std::vector<RegionTree> region_trees;
+  std::map<int, Region> regions;
+  std::vector<DrawableTreeRegionPrim> region_trees;
   //  (region-array           region-array                     :offset-assert 192)
   RegionArray region_array;
   //  (collide-hash           collide-hash                     :offset-assert 196)
@@ -156,7 +149,7 @@ struct LevelFile {
   //  (vis-spheres-length     uint32                           :offset        248)
 
   //  (region-tree            drawable-tree-region-prim        :offset        252)
-  RegionTree region_tree;
+  DrawableTreeRegionPrim region_tree;
   //  (tfrag-masks            texture-masks-array              :offset-assert 256)
   //  (tfrag-closest          (pointer float)                  :offset-assert 260)
   //  (tfrag-mask-count       uint32                           :offset        260)
@@ -176,6 +169,6 @@ struct LevelFile {
   //  (bsp-scale              vector :inline                   :offset-assert 288)
   //  (bsp-offset             vector :inline                   :offset-assert 304)
 
-  std::vector<u8> save_object_file() const;
+  std::vector<u8> save_object_file();
 };
 }  // namespace jak2
\ No newline at end of file
diff --git a/goalc/build_level/jak2/Region.cpp b/goalc/build_level/jak2/Region.cpp
new file mode 100644
index 0000000000..ae2c884590
--- /dev/null
+++ b/goalc/build_level/jak2/Region.cpp
@@ -0,0 +1,423 @@
+#include "Region.h"
+
+#include "Entity.h"
+
+#include "common/log/log.h"
+
+namespace jak2 {
+
+std::optional<std::map<std::string, size_t>> g_entity_slots;
+std::optional<std::map<int, size_t>> g_actor_group_slots;
+
+std::map<std::string, size_t> make_entity_slot_map(std::vector<EntityActor>* actors) {
+  std::map<std::string, size_t> result{};
+  if (actors) {
+    for (const auto& e : *actors) {
+      result.emplace(e.name, e.slot);
+    }
+  }
+  return result;
+}
+
+std::map<int, size_t> make_actor_group_slot_list(std::vector<ActorGroup>* actor_groups) {
+  std::map<int, size_t> result{};
+  if (actor_groups) {
+    for (const auto& e : *actor_groups) {
+      result.emplace(e.id, e.slot);
+    }
+  }
+  return result;
+}
+
+size_t gen_pair(DataObjectGenerator& gen, const goos::Object& pair) {
+  return gen.add_pair(pair, g_entity_slots, g_actor_group_slots);
+}
+
+void Region::generate_pairs(DataObjectGenerator& gen, const std::vector<size_t>& pair_slots) {
+  auto on_enter_slot = pair_slots[0];
+  auto on_inside_slot = pair_slots[1];
+  auto on_exit_slot = pair_slots[2];
+  size_t on_enter_byte = 0;
+  size_t on_inside_byte = 0;
+  size_t on_exit_byte = 0;
+  if (on_enter.has_value()) {
+    on_enter_byte = gen_pair(gen, *on_enter.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_enter_slot);
+  }
+  if (on_inside.has_value()) {
+    on_inside_byte = gen_pair(gen, *on_inside.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_inside_slot);
+  }
+  if (on_exit.has_value()) {
+    on_exit_byte = gen_pair(gen, *on_exit.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_exit_slot);
+  }
+  if (on_enter.has_value()) {
+    gen.link_word_to_byte(on_enter_slot, on_enter_byte);
+  }
+  if (on_inside.has_value()) {
+    gen.link_word_to_byte(on_inside_slot, on_inside_byte);
+  }
+  if (on_exit.has_value()) {
+    gen.link_word_to_byte(on_exit_slot, on_exit_byte);
+  }
+}
+
+size_t Region::generate(DataObjectGenerator& gen) const {
+  auto region_slot = gen.add_word(id);
+  auto on_enter_slot = gen.add_word(0);
+  auto on_inside_slot = gen.add_word(0);
+  auto on_exit_slot = gen.add_word(0);
+  size_t on_enter_byte = 0;
+  size_t on_inside_byte = 0;
+  size_t on_exit_byte = 0;
+  if (on_enter.has_value()) {
+    on_enter_byte = gen_pair(gen, *on_enter.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_enter_slot);
+  }
+  if (on_inside.has_value()) {
+    on_inside_byte = gen_pair(gen, *on_inside.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_inside_slot);
+  }
+  if (on_exit.has_value()) {
+    on_exit_byte = gen_pair(gen, *on_exit.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_exit_slot);
+  }
+  if (on_enter.has_value()) {
+    gen.link_word_to_byte(on_enter_slot, on_enter_byte);
+  }
+  if (on_inside.has_value()) {
+    gen.link_word_to_byte(on_inside_slot, on_inside_byte);
+  }
+  if (on_exit.has_value()) {
+    gen.link_word_to_byte(on_exit_slot, on_exit_byte);
+  }
+  return region_slot;
+}
+
+size_t RegionArray::generate(DataObjectGenerator& gen) {
+  g_entity_slots = make_entity_slot_map(entities);
+  g_actor_group_slots = make_actor_group_slot_list(actor_groups);
+  gen.align_to_basic();
+  gen.add_type_tag("region-array");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(data.size());  // 4 (length)
+  gen.add_word(data.size());  // 8 (allocated-length)
+  gen.add_word(0);            // 12
+  ASSERT((gen.current_offset_bytes() % 16) == 0);
+  for (auto& region : data) {
+    std::vector<size_t> pairs;
+    region->slot = gen.add_word(region->id);
+    pairs.push_back(gen.add_word(0));
+    pairs.push_back(gen.add_word(0));
+    pairs.push_back(gen.add_word(0));
+    pair_slots.emplace(region->id, pairs);
+    region_slots.emplace(region->id, region->slot);
+    // region->slot = region->generate(gen);
+  }
+  for (auto& region : data) {
+    auto pairs = pair_slots.find(region->id);
+    if (pairs != pair_slots.end()) {
+      region->generate_pairs(gen, pairs->second);
+    }
+  }
+  return result;
+}
+
+size_t generate_drawable_tree_region_prim_array(DataObjectGenerator& gen,
+                                                RegionArray& regions,
+                                                const std::vector<DrawableTreeRegionPrim>& trees) {
+  gen.align_to_basic();
+  gen.add_type_tag("array");
+  size_t result = gen.current_offset_bytes();
+  auto length = trees.size();
+  std::vector<size_t> tree_slots;
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_type_tag("drawable-tree-region-prim");
+  tree_slots.reserve(trees.size());
+  for (auto& tree : trees) {
+    tree_slots.push_back(gen.add_word(0));
+  }
+  gen.align(4);
+  regions.slot = regions.generate(gen);
+  for (int i = 0; i < trees.size(); i++) {
+    gen.link_word_to_byte(tree_slots[i], trees[i].generate(gen));
+  }
+  return result;
+}
+
+size_t DrawableTreeRegionPrim::generate(DataObjectGenerator& gen) const {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-tree-region-prim");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(1 << 16);      // 4, 6 (length)
+  gen.add_symbol_link(name);  // 8
+  gen.add_word(0);
+  gen.add_word_float(bsphere.x());
+  gen.add_word_float(bsphere.y());
+  gen.add_word_float(bsphere.z());
+  gen.add_word_float(bsphere.w());
+  size_t arr_slot = gen.add_word(0);
+  gen.align(4);
+  gen.link_word_to_byte(arr_slot, data2.generate(gen));
+  return result;
+}
+
+size_t DrawableInlineArrayRegionPrim::generate(DataObjectGenerator& gen) const {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-inline-array-region-prim");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(data.size() << 16);  // 4, 6 (length)
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  for (auto& prim : data) {
+    prim->generate(gen);
+  }
+  // second pass to fill in face and volume references
+  for (auto& prim : data) {
+    if (dynamic_cast<DrawableRegionFace*>(prim)) {
+      auto face = dynamic_cast<DrawableRegionFace*>(prim);
+      gen.link_word_to_byte(face->face_data_slot, face->data.generate(gen));
+    }
+    if (dynamic_cast<DrawableRegionVolume*>(prim)) {
+      auto vol = dynamic_cast<DrawableRegionVolume*>(prim);
+      gen.link_word_to_byte(vol->face_array_slot, vol->faces.generate(gen));
+    }
+  }
+  return result;
+}
+
+void fill_region_trees(std::vector<DrawableTreeRegionPrim>& trees,
+                       std::map<int, Region>& regions,
+                       RegionArray& region_arr,
+                       const nlohmann::json& json,
+                       u32 base_id) {
+  for (const auto& [k, tree_json] : json.items()) {
+    ASSERT_MSG(tree_json.is_object(), fmt::format("key \"{}\" is not an object.", k));
+    if (tree_json.is_object() && !tree_json.empty()) {
+      auto& tree = trees.emplace_back(k);
+      tree.bsphere = vectorm4_from_json(tree_json.at("bsphere"));
+      add_regions_from_json(tree_json.at("regions"), tree, regions, base_id);
+      for (auto& [id, region] : regions) {
+        if (region.tree == tree.name) {
+          DrawableRegionPrim* prim = nullptr;
+          if (region.shape == "sphere") {
+            prim = new DrawableRegionSphere(&region);
+            tree.data2.data.push_back(prim);
+          } else if (region.shape == "face") {
+            prim = new DrawableRegionFace(&region);
+            tree.data2.data.push_back(prim);
+          } else if (region.shape == "volume") {
+            prim = new DrawableRegionVolume(&region);
+            tree.data2.data.push_back(prim);
+          } else {
+            ASSERT_MSG(false, fmt::format("Invalid region shape \"{}\"", region.shape));
+          }
+        }
+      }
+    }
+  }
+  for (auto& [id, region] : regions) {
+    region_arr.data.push_back(&region);
+  }
+}
+
+void add_regions_from_json(const nlohmann::json& json,
+                           DrawableTreeRegionPrim& tree,
+                           std::map<int, Region>& regions,
+                           u32 base_id) {
+  std::vector<Region> result;
+  auto& reader = pretty_print::get_pretty_printer_reader();
+  for (const auto& region_json : json) {
+    auto id = region_json.value("id", base_id + regions.size());
+    auto p = regions.emplace(id, Region());
+    if (p.second) {
+      auto& region = p.first->second;
+      result.push_back(region);
+      region.id = region_json.value("id", base_id + regions.size());
+      region.tree = tree.name;
+      region.shape = region_json.at("shape").get<std::string>();
+      region.bsphere = vectorm4_from_json(region_json.at("bsphere"));
+      ASSERT_MSG(region.shape == "sphere" || region.shape == "face" || region.shape == "volume",
+                 "Region must have shape 'sphere', 'face' or 'volume'.");
+      if (region.shape == "sphere") {
+        region.faces = std::nullopt;
+      }
+      if (region.shape == "face") {
+        ASSERT_MSG(region_json.find("face") != region_json.end(),
+                   "Face region must have 'face' key.");
+        auto face = region_json.at("face").get<RegionFaceData>();
+        std::vector<RegionFaceData> faces;
+        faces.push_back(face);
+        region.faces = std::make_optional<std::vector<RegionFaceData>>(faces);
+      }
+      if (region.shape == "volume") {
+        ASSERT_MSG(region_json.find("volume") != region_json.end(),
+                   "Volume region must have 'volume' key.");
+        auto arr = region_json.at("volume").get<RegionFaceArray>();
+        region.faces = std::make_optional<std::vector<RegionFaceData>>(arr.faces);
+      }
+      if (region_json.find("on-enter") != region_json.end()) {
+        region.on_enter = std::make_optional(
+            &reader.read_from_string(region_json.at("on-enter").get<std::string>(), false)
+                 .as_pair()
+                 ->car);
+      }
+      if (region_json.find("on-inside") != region_json.end()) {
+        region.on_inside = std::make_optional(
+            &reader.read_from_string(region_json.at("on-inside").get<std::string>(), false)
+                 .as_pair()
+                 ->car);
+      }
+      if (region_json.find("on-exit") != region_json.end()) {
+        region.on_exit = std::make_optional(
+            &reader.read_from_string(region_json.at("on-exit").get<std::string>(), false)
+                 .as_pair()
+                 ->car);
+      }
+      lg::print(region.print());
+    } else {
+      lg::warn("Duplicate region with ID {} in tree {}, skipped", p.first->first, tree.name);
+    }
+  }
+}
+
+std::string Region::print() {
+  std::string result;
+  result += fmt::format("Region {} ({}):\n", id, tree);
+  result += fmt::format("  shape: {}\n", shape);
+  if (on_enter.has_value()) {
+    result += fmt::format("  on-enter: {}\n", on_enter.value()->print());
+  } else {
+    result += fmt::format("  on-enter: #f\n");
+  }
+  if (on_inside.has_value()) {
+    result += fmt::format("  on-inside: {}\n", on_inside.value()->print());
+  } else {
+    result += fmt::format("  on-inside: #f\n");
+  }
+  if (on_exit.has_value()) {
+    result += fmt::format("  on-exit: {}\n", on_exit.value()->print());
+  } else {
+    result += fmt::format("  on-exit: #f\n");
+  }
+  return result;
+}
+
+void from_json(const nlohmann::json& json, RegionFaceData& obj) {
+  obj.normal = vector_from_json(json.at("normal"));
+  obj.normal.w() *= METER_LENGTH;
+  std::vector<math::Vector4f> points;
+  for (auto& p : json.at("points")) {
+    points.push_back(vectorm3_from_json(p));
+  }
+  obj.num_points = points.size();
+  obj.points = points;
+}
+
+void from_json(const nlohmann::json& json, RegionFaceArray& obj) {
+  (void)obj;
+  for (const auto& face_json : json.at("faces")) {
+    RegionFaceData face;
+    from_json(face_json, face);
+    obj.faces.push_back(face);
+  }
+}
+
+size_t RegionFaceData::generate(DataObjectGenerator& gen) {
+  size_t result = gen.current_offset_bytes();
+  gen.add_word_float(normal.x());
+  gen.add_word_float(normal.y());
+  gen.add_word_float(normal.z());
+  gen.add_word_float(normal.w());
+  gen.add_word(num_points);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  for (auto& p : points) {
+    gen.add_word_float(p.x());
+    gen.add_word_float(p.y());
+    gen.add_word_float(p.z());
+    gen.add_word_float(p.w());
+  }
+  return result;
+}
+
+size_t RegionFaceArray::generate(DataObjectGenerator& gen) {
+  gen.align_to_basic();
+  gen.add_type_tag("region-face-array");
+  size_t result = gen.current_offset_bytes();
+  auto length = data.size();
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_word(0);
+  for (auto& face : data) {
+    face.generate(gen);
+  }
+  for (int i = 0; i < data.size(); i++) {
+    auto face = data[i];
+    auto face0 = face.data;
+    gen.link_word_to_byte(face.face_data_slot, face0.generate(gen));
+  }
+  return result;
+}
+
+size_t DrawableRegionPrim::generate(DataObjectGenerator& gen) {
+  return 0;
+}
+
+size_t DrawableRegionSphere::generate(DataObjectGenerator& gen) {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-region-sphere");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(region->id);
+  gen.link_word_to_word(gen.add_word(0), region->slot);
+  gen.add_word(0);
+  gen.add_word_float(region->bsphere.x());
+  gen.add_word_float(region->bsphere.y());
+  gen.add_word_float(region->bsphere.z());
+  gen.add_word_float(region->bsphere.w());
+  return result;
+}
+
+size_t DrawableRegionVolume::generate(DataObjectGenerator& gen
+                                      /*size_t region_face_array_slot*/) {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-region-volume");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(region->id);
+  gen.link_word_to_word(gen.add_word(0), region->slot);
+  face_array_slot = gen.add_word(0);
+  gen.add_word_float(region->bsphere.x());
+  gen.add_word_float(region->bsphere.y());
+  gen.add_word_float(region->bsphere.z());
+  gen.add_word_float(region->bsphere.w());
+  return result;
+}
+
+size_t DrawableRegionFace::generate(DataObjectGenerator& gen) {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-region-face");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(region->id);
+  gen.link_word_to_word(gen.add_word(0), region->slot);
+  face_data_slot = gen.add_word(0);
+  const auto& bsphere = bsphere_override.has_value() ? bsphere_override.value() : region->bsphere;
+  gen.add_word_float(bsphere.x());
+  gen.add_word_float(bsphere.y());
+  gen.add_word_float(bsphere.z());
+  gen.add_word_float(bsphere.w());
+  return result;
+}
+}  // namespace jak2
diff --git a/goalc/build_level/jak2/Region.h b/goalc/build_level/jak2/Region.h
new file mode 100644
index 0000000000..27055b23ee
--- /dev/null
+++ b/goalc/build_level/jak2/Region.h
@@ -0,0 +1,207 @@
+#pragma once
+
+#include <cmath>
+#include <string>
+
+#include "Entity.h"
+
+#include "common/common_types.h"
+#include "common/goos/ParseHelpers.h"
+#include "common/goos/Printer.h"
+#include "common/math/Vector.h"
+
+#include "goalc/data_compiler/DataObjectGenerator.h"
+
+#include "third-party/json.hpp"
+
+namespace jak2 {
+
+struct RegionFaceData {
+  // (normal        vector  :inline  :offset-assert 0)
+  // (normal-offset float            :offset 12)
+  // (num-points    uint32           :offset-assert 16)
+  // (points        vector :inline :dynamic :offset-assert 32) ;; guess
+  math::Vector4f normal;  // w component is normal offset
+  u32 num_points;
+  std::vector<math::Vector4f> points;
+
+  size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+void from_json(const json& j, RegionFaceData& obj);
+
+struct RegionFaceArray;
+
+struct Region {
+  // (id        uint32  :offset-assert 0)
+  // (on-enter  pair    :offset-assert 4)
+  // (on-inside pair    :offset-assert 8)
+  // (on-exit   pair    :offset-assert 12)
+  u32 id;
+  std::optional<goos::Object*> on_enter;
+  std::optional<goos::Object*> on_inside;
+  std::optional<goos::Object*> on_exit;
+  math::Vector4f trans;
+  math::Vector4f bsphere;
+  std::string tree;   // target, camera, data, water, city_vis, sample, light, entity
+  std::string shape;  // sphere, face, volume
+  std::optional<std::vector<RegionFaceData>> faces;
+
+  size_t slot;
+  std::optional<std::map<std::string, size_t>> actor_slots;
+
+  size_t generate(DataObjectGenerator& gen) const;
+  void generate_pairs(DataObjectGenerator& gen, const std::vector<size_t>& pair_slots);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+  std::string print();
+};
+
+struct RegionArray {
+  // (data             region :inline :dynamic :offset-assert 16)
+  std::vector<Region*> data;
+  std::map<int, std::vector<size_t>> pair_slots;
+  std::map<int, size_t> region_slots;
+  std::map<std::string, size_t> entity_actor_slots;
+  std::vector<EntityActor>* entities;
+  std::vector<ActorGroup>* actor_groups;
+
+  size_t slot;
+
+  size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t region_array) const;
+};
+
+struct DrawableRegionPrim {
+  // (deftype drawable-region-prim (drawable)
+  //  ((region region  :offset 8)
+  //   )
+  Region* region;
+
+  explicit DrawableRegionPrim(Region* region) { this->region = region; }
+
+  virtual size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+struct DrawableInlineArrayRegionPrim {
+  // (deftype drawable-inline-array-region-prim (drawable-inline-array)
+  //  ((data drawable-region-prim 1 :inline :offset-assert 32)
+  //  )
+  std::vector<DrawableRegionPrim*> data;
+
+  size_t generate(DataObjectGenerator& gen) const;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+struct DrawableTreeRegionPrim {
+  // (deftype drawable-tree-region-prim (drawable-tree)
+  // ((id      int16  :offset-assert 4)
+  //  (length  int16  :offset 6)
+  //  (name    symbol :offset 8)
+  //  (bsphere vector :inline :offset-assert 16)
+  //  (data2   drawable-inline-array :dynamic :offset 32 :score 1))
+  //  )
+  std::string name;
+  math::Vector4f bsphere;
+  DrawableInlineArrayRegionPrim data2;
+
+  DrawableTreeRegionPrim() = default;
+  explicit DrawableTreeRegionPrim(std::string name_) : name(std::move(name_)) {}
+
+  size_t generate(DataObjectGenerator& gen) const;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+size_t generate_drawable_tree_region_prim_array(DataObjectGenerator& gen,
+                                                RegionArray& regions,
+                                                const std::vector<DrawableTreeRegionPrim>& trees);
+
+void fill_region_trees(std::vector<DrawableTreeRegionPrim>& trees,
+                       std::map<int, Region>& regions,
+                       RegionArray& region_arr,
+                       const nlohmann::json& json,
+                       u32 base_id);
+void add_regions_from_json(const nlohmann::json& json,
+                           DrawableTreeRegionPrim& tree,
+                           std::map<int, Region>& regions,
+                           u32 base_id);
+
+struct DrawableRegionSphere : DrawableRegionPrim {
+  using DrawableRegionPrim::DrawableRegionPrim;
+  size_t generate(DataObjectGenerator& gen) override;
+};
+
+struct DrawableRegionFace : DrawableRegionPrim {
+  // (deftype drawable-region-face (drawable-region-prim)
+  //  ((data region-face-data  :offset 12)
+  //   )
+  RegionFaceData data;
+  size_t face_data_slot;
+  std::optional<math::Vector4f> bsphere_override;
+
+  explicit DrawableRegionFace(Region* region) : DrawableRegionPrim(region) {
+    if (region->faces.has_value()) {
+      data = region->faces.value().at(0);
+    }
+  }
+  size_t generate(DataObjectGenerator& gen) override;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+struct RegionFaceArray {
+  // (deftype region-face-array (inline-array-class)
+  //  ((data drawable-region-face :inline :dynamic :offset 16)
+  //   )
+  std::vector<DrawableRegionFace> data;
+  std::vector<RegionFaceData> faces;
+
+  size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+void from_json(const json& j, RegionFaceArray& obj);
+
+struct DrawableRegionVolume : DrawableRegionPrim {
+  // (deftype drawable-region-volume (drawable-region-prim)
+  //  ((faces region-face-array  :offset 12)
+  //   )
+  RegionFaceArray faces;
+  size_t face_array_slot;
+
+  explicit DrawableRegionVolume(Region* region) : DrawableRegionPrim(region) {
+    if (this->region->faces.has_value()) {
+      auto face_arr = this->region->faces.value();
+      for (const auto& f : face_arr) {
+        auto& face = faces.data.emplace_back(region);
+        face.data = f;
+        // compute per-face bsphere from the face's points for volumes
+        if (!f.points.empty()) {
+          math::Vector4f center = {0, 0, 0, 0};
+          for (auto& pt : f.points) {
+            center.x() += pt.x();
+            center.y() += pt.y();
+            center.z() += pt.z();
+          }
+          auto n = static_cast<float>(f.points.size());
+          center.x() /= n;
+          center.y() /= n;
+          center.z() /= n;
+          float max_dist_sq = 0;
+          for (auto& pt : f.points) {
+            float dx = pt.x() - center.x();
+            float dy = pt.y() - center.y();
+            float dz = pt.z() - center.z();
+            max_dist_sq = std::max(max_dist_sq, dx * dx + dy * dy + dz * dz);
+          }
+          center.w() = std::sqrt(max_dist_sq);
+          face.bsphere_override = center;
+        }
+      }
+    }
+  }
+
+  size_t generate(DataObjectGenerator& gen) override;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+}  // namespace jak2
\ No newline at end of file
diff --git a/goalc/build_level/jak2/build_level.cpp b/goalc/build_level/jak2/build_level.cpp
index b350ffac9a..0458599f8d 100644
--- a/goalc/build_level/jak2/build_level.cpp
+++ b/goalc/build_level/jak2/build_level.cpp
@@ -9,6 +9,7 @@
 #include "goalc/build_level/jak2/Entity.h"
 #include "goalc/build_level/jak2/FileInfo.h"
 #include "goalc/build_level/jak2/LevelFile.h"
+#include <decompiler/level_extractor/extract_collide_frags.h>
 
 namespace jak2 {
 bool run_build_level(const std::string& input_file,
@@ -60,9 +61,19 @@ bool run_build_level(const std::string& input_file,
              fmt::format("Actor IDs must be unique. Found at least two actors with ID {}",
                          duplicates->aid));
   file.actors = std::move(actors);
+  // actor groups
+  if (level_json.contains("actor_groups") && !level_json.at("actor_groups").empty()) {
+    add_actor_groups_from_json(level_json.at("actor_groups"), file.actors, file.actor_groups, 0);
+  }
   // cameras
   // nodes
   // regions
+  if (level_json.contains("region_trees") && !level_json.at("region_trees").empty()) {
+    file.region_array.entities = &file.actors;
+    file.region_array.actor_groups = &file.actor_groups;
+    fill_region_trees(file.region_trees, file.regions, file.region_array,
+                      level_json.at("region_trees"), level_json.value("base_region_id", 0));
+  }
   // subdivs
   // actor birth
   for (size_t i = 0; i < file.actors.size(); i++) {
@@ -89,6 +100,22 @@ bool run_build_level(const std::string& input_file,
     lg::error("No collision geometry was found");
   } else {
     file.collide_hash = construct_collide_hash(mesh_extract_out.collide.faces);
+    // for collision renderer
+    for (auto& face : mesh_extract_out.collide.faces) {
+      math::Vector4f verts[3];
+      for (int i = 0; i < 3; i++) {
+        verts[i].x() = face.v[i].x();
+        verts[i].y() = face.v[i].y();
+        verts[i].z() = face.v[i].z();
+        verts[i].w() = 1.f;
+      }
+      tfrag3::CollisionMesh::Vertex out_verts[3];
+      decompiler::set_vertices_for_tri(out_verts, verts);
+      for (auto& out : out_verts) {
+        out.pat = face.pat.val;
+        pc_level.collision.vertices.push_back(out);
+      }
+    }
   }
 
   // Save the GOAL level
diff --git a/goalc/build_level/jak3/Entity.cpp b/goalc/build_level/jak3/Entity.cpp
index a31fd2c4c2..41a0676d9a 100644
--- a/goalc/build_level/jak3/Entity.cpp
+++ b/goalc/build_level/jak3/Entity.cpp
@@ -39,8 +39,7 @@ size_t generate_drawable_actor(DataObjectGenerator& gen,
   return result;
 }
 
-size_t generate_inline_array_actors(DataObjectGenerator& gen,
-                                    const std::vector<EntityActor>& actors) {
+size_t generate_inline_array_actors(DataObjectGenerator& gen, std::vector<EntityActor>& actors) {
   std::vector<size_t> actor_locs;
   for (auto& actor : actors) {
     actor_locs.push_back(actor.generate(gen));
@@ -62,6 +61,7 @@ size_t generate_inline_array_actors(DataObjectGenerator& gen,
   ASSERT((gen.current_offset_bytes() % 16) == 0);
 
   for (size_t i = 0; i < actors.size(); i++) {
+    actors[i].slot = actor_locs[i];
     generate_drawable_actor(gen, actors[i], actor_locs[i]);
   }
   return result;
@@ -94,10 +94,13 @@ void add_actors_from_json(const nlohmann::json& json,
     actor.bsphere = vectorm4_from_json(actor_json.at("bsphere"));
 
     if (actor_json.find("lump") != actor_json.end()) {
-      for (auto [key, value] : actor_json.at("lump").items()) {
+      for (auto& [key, value] : actor_json.at("lump").items()) {
         if (value.is_string()) {
           std::string value_string = value.get<std::string>();
-          if (value_string.size() > 0 && value_string[0] == '\'') {
+          if (key == "name") {
+            actor.name = value_string;
+          }
+          if (!value_string.empty() && value_string[0] == '\'') {
             actor.res_lump.add_res(
                 std::make_unique<ResSymbol>(key, value_string.substr(1), -1000000000.0000));
           } else {
@@ -115,4 +118,62 @@ void add_actors_from_json(const nlohmann::json& json,
     actor.res_lump.sort_res();
   }
 }
+
+size_t generate_actor_group(DataObjectGenerator& gen, const ActorGroup& group) {
+  gen.align_to_basic();
+  gen.add_type_tag("actor-group");
+  size_t result = gen.current_offset_bytes();
+  auto length = group.actors.size();
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_type_tag("entity-actor");
+  for (auto& actor : group.actors) {
+    gen.link_word_to_byte(gen.add_word(0), actor->slot);
+    gen.add_word(actor->aid);
+  }
+  gen.align(4);
+  return result;
+}
+
+size_t generate_actor_group_array(DataObjectGenerator& gen, std::vector<ActorGroup>& actor_groups) {
+  gen.align_to_basic();
+  gen.add_type_tag("array");
+  size_t result = gen.current_offset_bytes();
+  auto length = actor_groups.size();
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_type_tag("actor-group");
+  std::vector<size_t> group_slots;
+  for (auto& group : actor_groups) {
+    group_slots.push_back(gen.add_word(0));
+  }
+  gen.align(4);
+  for (int i = 0; i < group_slots.size(); i++) {
+    actor_groups.at(i).slot = generate_actor_group(gen, actor_groups.at(i));
+    gen.link_word_to_byte(group_slots.at(i), actor_groups.at(i).slot);
+  }
+
+  return result;
+}
+
+void add_actor_groups_from_json(const nlohmann::json& json,
+                                const std::vector<EntityActor>& actors,
+                                std::vector<ActorGroup>& actor_groups,
+                                u32 base_id) {
+  for (const auto& actor_group : json) {
+    auto& group = actor_groups.emplace_back();
+    group.id = actor_group.value("id", base_id + actor_groups.size());
+    auto entity_list = actor_group.value<std::vector<std::string>>("entities", {});
+    for (auto& ent_name : entity_list) {
+      auto ent = std::ranges::find_if(
+          actors, [ent_name](const EntityActor& actor) { return actor.name == ent_name; });
+      if (ent != actors.end()) {
+        group.actors.push_back(&*ent);
+      } else {
+        ASSERT_MSG(false, fmt::format("Failed to find actor \"{}\", declared in actor group id {}.",
+                                      ent_name, group.id));
+      }
+    }
+  }
+}
 }  // namespace jak3
diff --git a/goalc/build_level/jak3/Entity.h b/goalc/build_level/jak3/Entity.h
index f4ae154583..eab1ba1291 100644
--- a/goalc/build_level/jak3/Entity.h
+++ b/goalc/build_level/jak3/Entity.h
@@ -13,6 +13,7 @@ namespace jak3 {
  *  (quat quaternion :inline :offset-assert 64)
  */
 struct EntityActor {
+  std::string name;
   ResLump res_lump;
   math::Vector4f trans;  // w = 1 here
   u32 aid = 0;
@@ -24,14 +25,26 @@ struct EntityActor {
 
   math::Vector4f bsphere;
 
+  size_t slot;
+
   size_t generate(DataObjectGenerator& gen) const;
 };
 
-size_t generate_inline_array_actors(DataObjectGenerator& gen,
-                                    const std::vector<EntityActor>& actors);
+struct ActorGroup {
+  u64 id;
+  std::vector<const EntityActor*> actors;
+  size_t slot;
+};
+
+size_t generate_inline_array_actors(DataObjectGenerator& gen, std::vector<EntityActor>& actors);
+size_t generate_actor_group_array(DataObjectGenerator& gen, std::vector<ActorGroup>& actor_groups);
 
 void add_actors_from_json(const nlohmann::json& json,
                           std::vector<EntityActor>& actor_list,
                           u32 base_aid,
                           decompiler::DecompilerTypeSystem& dts);
+void add_actor_groups_from_json(const nlohmann::json& json,
+                                const std::vector<EntityActor>& actors,
+                                std::vector<ActorGroup>& actor_groups,
+                                u32 base_id);
 }  // namespace jak3
\ No newline at end of file
diff --git a/goalc/build_level/jak3/LevelFile.cpp b/goalc/build_level/jak3/LevelFile.cpp
index 6154b36080..0a51130cb1 100644
--- a/goalc/build_level/jak3/LevelFile.cpp
+++ b/goalc/build_level/jak3/LevelFile.cpp
@@ -66,7 +66,7 @@ size_t generate_u32_array(const std::vector<u32>& array, DataObjectGenerator& ge
   return result;
 }
 
-std::vector<u8> LevelFile::save_object_file() const {
+std::vector<u8> LevelFile::save_object_file() {
   DataObjectGenerator gen;
   gen.add_type_tag("bsp-header");
 
@@ -114,8 +114,12 @@ std::vector<u8> LevelFile::save_object_file() const {
   //(light-hash             light-hash                       :offset-assert 176)
   //(nav-meshes             (array entity-nav-mesh)          :offset-assert 180)
   //(actor-groups           (array actor-group)              :offset-assert 184)
+  gen.link_word_to_byte(184 / 4, generate_actor_group_array(gen, actor_groups));
   //(region-trees           (array drawable-tree-region-prim) :offset-assert 188)
+  gen.link_word_to_byte(188 / 4,
+                        generate_drawable_tree_region_prim_array(gen, region_array, region_trees));
   //(region-array           region-array                     :offset-assert 192)
+  gen.link_word_to_byte(192 / 4, region_array.slot);
   //(collide-hash           collide-hash                     :offset-assert 196)
   gen.link_word_to_byte(196 / 4, add_to_object_file(collide_hash, gen));
   //(wind-array             uint32                           :offset        200)
diff --git a/goalc/build_level/jak3/LevelFile.h b/goalc/build_level/jak3/LevelFile.h
index 996592bd75..f7dd7d4d1b 100644
--- a/goalc/build_level/jak3/LevelFile.h
+++ b/goalc/build_level/jak3/LevelFile.h
@@ -12,6 +12,7 @@
 #include "goalc/build_level/common/Tie.h"
 #include "goalc/build_level/jak3/Entity.h"
 #include "goalc/build_level/jak3/FileInfo.h"
+#include "goalc/build_level/jak3/Region.h"
 
 namespace jak3 {
 struct VisibilityString {
@@ -22,8 +23,6 @@ struct DrawableTreeActor {};
 
 struct DrawableTreeInstanceShrub {};
 
-struct DrawableTreeRegionPrim {};
-
 struct DrawableTreeArray {
   std::vector<DrawableTreeTfrag> tfrags;
   std::vector<DrawableTreeInstanceTie> ties;
@@ -49,12 +48,6 @@ struct LightHash {};
 
 struct EntityNavMesh {};
 
-struct ActorGroup {};
-
-struct RegionTree {};
-
-struct RegionArray {};
-
 struct CityLevelInfo {};
 
 struct TextureMasksArray {};
@@ -141,7 +134,8 @@ struct LevelFile {
   //  (actor-groups           (array actor-group)              :offset-assert 184)
   std::vector<ActorGroup> actor_groups;
   //  (region-trees           (array drawable-tree-region-prim) :offset-assert 188)
-  std::vector<RegionTree> region_trees;
+  std::map<int, Region> regions;
+  std::vector<DrawableTreeRegionPrim> region_trees;
   //  (region-array           region-array                     :offset-assert 192)
   RegionArray region_array;
   //  (collide-hash           collide-hash                     :offset-assert 196)
@@ -156,7 +150,7 @@ struct LevelFile {
   //  (vis-spheres-length     uint32                           :offset        248)
 
   //  (region-tree            drawable-tree-region-prim        :offset        252)
-  RegionTree region_tree;
+  DrawableTreeRegionPrim region_tree;
   //  (tfrag-masks            texture-masks-array              :offset-assert 256)
   //  (tfrag-closest          (pointer float)                  :offset-assert 260)
   //  (tfrag-mask-count       uint32                           :offset        260)
@@ -176,6 +170,6 @@ struct LevelFile {
   //  (bsp-scale              vector :inline                   :offset-assert 288)
   //  (bsp-offset             vector :inline                   :offset-assert 304)
 
-  std::vector<u8> save_object_file() const;
+  std::vector<u8> save_object_file();
 };
 }  // namespace jak3
\ No newline at end of file
diff --git a/goalc/build_level/jak3/Region.cpp b/goalc/build_level/jak3/Region.cpp
new file mode 100644
index 0000000000..c10a00f695
--- /dev/null
+++ b/goalc/build_level/jak3/Region.cpp
@@ -0,0 +1,423 @@
+#include "Region.h"
+
+#include "Entity.h"
+
+#include "common/log/log.h"
+
+namespace jak3 {
+
+std::optional<std::map<std::string, size_t>> g_entity_slots;
+std::optional<std::map<int, size_t>> g_actor_group_slots;
+
+std::map<std::string, size_t> make_entity_slot_map(std::vector<EntityActor>* actors) {
+  std::map<std::string, size_t> result{};
+  if (actors) {
+    for (const auto& e : *actors) {
+      result.emplace(e.name, e.slot);
+    }
+  }
+  return result;
+}
+
+std::map<int, size_t> make_actor_group_slot_list(std::vector<ActorGroup>* actor_groups) {
+  std::map<int, size_t> result{};
+  if (actor_groups) {
+    for (const auto& e : *actor_groups) {
+      result.emplace(e.id, e.slot);
+    }
+  }
+  return result;
+}
+
+size_t gen_pair(DataObjectGenerator& gen, const goos::Object& pair) {
+  return gen.add_pair(pair, g_entity_slots, g_actor_group_slots);
+}
+
+void Region::generate_pairs(DataObjectGenerator& gen, const std::vector<size_t>& pair_slots) {
+  auto on_enter_slot = pair_slots[0];
+  auto on_inside_slot = pair_slots[1];
+  auto on_exit_slot = pair_slots[2];
+  size_t on_enter_byte = 0;
+  size_t on_inside_byte = 0;
+  size_t on_exit_byte = 0;
+  if (on_enter.has_value()) {
+    on_enter_byte = gen_pair(gen, *on_enter.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_enter_slot);
+  }
+  if (on_inside.has_value()) {
+    on_inside_byte = gen_pair(gen, *on_inside.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_inside_slot);
+  }
+  if (on_exit.has_value()) {
+    on_exit_byte = gen_pair(gen, *on_exit.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_exit_slot);
+  }
+  if (on_enter.has_value()) {
+    gen.link_word_to_byte(on_enter_slot, on_enter_byte);
+  }
+  if (on_inside.has_value()) {
+    gen.link_word_to_byte(on_inside_slot, on_inside_byte);
+  }
+  if (on_exit.has_value()) {
+    gen.link_word_to_byte(on_exit_slot, on_exit_byte);
+  }
+}
+
+size_t Region::generate(DataObjectGenerator& gen) const {
+  auto region_slot = gen.add_word(id);
+  auto on_enter_slot = gen.add_word(0);
+  auto on_inside_slot = gen.add_word(0);
+  auto on_exit_slot = gen.add_word(0);
+  size_t on_enter_byte = 0;
+  size_t on_inside_byte = 0;
+  size_t on_exit_byte = 0;
+  if (on_enter.has_value()) {
+    on_enter_byte = gen_pair(gen, *on_enter.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_enter_slot);
+  }
+  if (on_inside.has_value()) {
+    on_inside_byte = gen_pair(gen, *on_inside.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_inside_slot);
+  }
+  if (on_exit.has_value()) {
+    on_exit_byte = gen_pair(gen, *on_exit.value());
+  } else {
+    gen.link_word_to_symbol("#f", on_exit_slot);
+  }
+  if (on_enter.has_value()) {
+    gen.link_word_to_byte(on_enter_slot, on_enter_byte);
+  }
+  if (on_inside.has_value()) {
+    gen.link_word_to_byte(on_inside_slot, on_inside_byte);
+  }
+  if (on_exit.has_value()) {
+    gen.link_word_to_byte(on_exit_slot, on_exit_byte);
+  }
+  return region_slot;
+}
+
+size_t RegionArray::generate(DataObjectGenerator& gen) {
+  g_entity_slots = make_entity_slot_map(entities);
+  g_actor_group_slots = make_actor_group_slot_list(actor_groups);
+  gen.align_to_basic();
+  gen.add_type_tag("region-array");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(data.size());  // 4 (length)
+  gen.add_word(data.size());  // 8 (allocated-length)
+  gen.add_word(0);            // 12
+  ASSERT((gen.current_offset_bytes() % 16) == 0);
+  for (auto& region : data) {
+    std::vector<size_t> pairs;
+    region->slot = gen.add_word(region->id);
+    pairs.push_back(gen.add_word(0));
+    pairs.push_back(gen.add_word(0));
+    pairs.push_back(gen.add_word(0));
+    pair_slots.emplace(region->id, pairs);
+    region_slots.emplace(region->id, region->slot);
+    // region->slot = region->generate(gen);
+  }
+  for (auto& region : data) {
+    auto pairs = pair_slots.find(region->id);
+    if (pairs != pair_slots.end()) {
+      region->generate_pairs(gen, pairs->second);
+    }
+  }
+  return result;
+}
+
+size_t generate_drawable_tree_region_prim_array(DataObjectGenerator& gen,
+                                                RegionArray& regions,
+                                                const std::vector<DrawableTreeRegionPrim>& trees) {
+  gen.align_to_basic();
+  gen.add_type_tag("array");
+  size_t result = gen.current_offset_bytes();
+  auto length = trees.size();
+  std::vector<size_t> tree_slots;
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_type_tag("drawable-tree-region-prim");
+  tree_slots.reserve(trees.size());
+  for (auto& tree : trees) {
+    tree_slots.push_back(gen.add_word(0));
+  }
+  gen.align(4);
+  regions.slot = regions.generate(gen);
+  for (int i = 0; i < trees.size(); i++) {
+    gen.link_word_to_byte(tree_slots[i], trees[i].generate(gen));
+  }
+  return result;
+}
+
+size_t DrawableTreeRegionPrim::generate(DataObjectGenerator& gen) const {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-tree-region-prim");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(1 << 16);      // 4, 6 (length)
+  gen.add_symbol_link(name);  // 8
+  gen.add_word(0);
+  gen.add_word_float(bsphere.x());
+  gen.add_word_float(bsphere.y());
+  gen.add_word_float(bsphere.z());
+  gen.add_word_float(bsphere.w());
+  size_t arr_slot = gen.add_word(0);
+  gen.align(4);
+  gen.link_word_to_byte(arr_slot, data2.generate(gen));
+  return result;
+}
+
+size_t DrawableInlineArrayRegionPrim::generate(DataObjectGenerator& gen) const {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-inline-array-region-prim");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(data.size() << 16);  // 4, 6 (length)
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  for (auto& prim : data) {
+    prim->generate(gen);
+  }
+  // second pass to fill in face and volume references
+  for (auto& prim : data) {
+    if (dynamic_cast<DrawableRegionFace*>(prim)) {
+      auto face = dynamic_cast<DrawableRegionFace*>(prim);
+      gen.link_word_to_byte(face->face_data_slot, face->data.generate(gen));
+    }
+    if (dynamic_cast<DrawableRegionVolume*>(prim)) {
+      auto vol = dynamic_cast<DrawableRegionVolume*>(prim);
+      gen.link_word_to_byte(vol->face_array_slot, vol->faces.generate(gen));
+    }
+  }
+  return result;
+}
+
+void fill_region_trees(std::vector<DrawableTreeRegionPrim>& trees,
+                       std::map<int, Region>& regions,
+                       RegionArray& region_arr,
+                       const nlohmann::json& json,
+                       u32 base_id) {
+  for (const auto& [k, tree_json] : json.items()) {
+    ASSERT_MSG(tree_json.is_object(), fmt::format("key \"{}\" is not an object.", k));
+    if (tree_json.is_object() && !tree_json.empty()) {
+      auto& tree = trees.emplace_back(k);
+      tree.bsphere = vectorm4_from_json(tree_json.at("bsphere"));
+      add_regions_from_json(tree_json.at("regions"), tree, regions, base_id);
+      for (auto& [id, region] : regions) {
+        if (region.tree == tree.name) {
+          DrawableRegionPrim* prim = nullptr;
+          if (region.shape == "sphere") {
+            prim = new DrawableRegionSphere(&region);
+            tree.data2.data.push_back(prim);
+          } else if (region.shape == "face") {
+            prim = new DrawableRegionFace(&region);
+            tree.data2.data.push_back(prim);
+          } else if (region.shape == "volume") {
+            prim = new DrawableRegionVolume(&region);
+            tree.data2.data.push_back(prim);
+          } else {
+            ASSERT_MSG(false, fmt::format("Invalid region shape \"{}\"", region.shape));
+          }
+        }
+      }
+    }
+  }
+  for (auto& [id, region] : regions) {
+    region_arr.data.push_back(&region);
+  }
+}
+
+void add_regions_from_json(const nlohmann::json& json,
+                           DrawableTreeRegionPrim& tree,
+                           std::map<int, Region>& regions,
+                           u32 base_id) {
+  std::vector<Region> result;
+  auto& reader = pretty_print::get_pretty_printer_reader();
+  for (const auto& region_json : json) {
+    auto id = region_json.value("id", base_id + regions.size());
+    auto p = regions.emplace(id, Region());
+    if (p.second) {
+      auto& region = p.first->second;
+      result.push_back(region);
+      region.id = region_json.value("id", base_id + regions.size());
+      region.tree = tree.name;
+      region.shape = region_json.at("shape").get<std::string>();
+      region.bsphere = vectorm4_from_json(region_json.at("bsphere"));
+      ASSERT_MSG(region.shape == "sphere" || region.shape == "face" || region.shape == "volume",
+                 "Region must have shape 'sphere', 'face' or 'volume'.");
+      if (region.shape == "sphere") {
+        region.faces = std::nullopt;
+      }
+      if (region.shape == "face") {
+        ASSERT_MSG(region_json.find("face") != region_json.end(),
+                   "Face region must have 'face' key.");
+        auto face = region_json.at("face").get<RegionFaceData>();
+        std::vector<RegionFaceData> faces;
+        faces.push_back(face);
+        region.faces = std::make_optional<std::vector<RegionFaceData>>(faces);
+      }
+      if (region.shape == "volume") {
+        ASSERT_MSG(region_json.find("volume") != region_json.end(),
+                   "Volume region must have 'volume' key.");
+        auto arr = region_json.at("volume").get<RegionFaceArray>();
+        region.faces = std::make_optional<std::vector<RegionFaceData>>(arr.faces);
+      }
+      if (region_json.find("on-enter") != region_json.end()) {
+        region.on_enter = std::make_optional(
+            &reader.read_from_string(region_json.at("on-enter").get<std::string>(), false)
+                 .as_pair()
+                 ->car);
+      }
+      if (region_json.find("on-inside") != region_json.end()) {
+        region.on_inside = std::make_optional(
+            &reader.read_from_string(region_json.at("on-inside").get<std::string>(), false)
+                 .as_pair()
+                 ->car);
+      }
+      if (region_json.find("on-exit") != region_json.end()) {
+        region.on_exit = std::make_optional(
+            &reader.read_from_string(region_json.at("on-exit").get<std::string>(), false)
+                 .as_pair()
+                 ->car);
+      }
+      lg::print(region.print());
+    } else {
+      lg::warn("Duplicate region with ID {} in tree {}, skipped", p.first->first, tree.name);
+    }
+  }
+}
+
+std::string Region::print() {
+  std::string result;
+  result += fmt::format("Region {} ({}):\n", id, tree);
+  result += fmt::format("  shape: {}\n", shape);
+  if (on_enter.has_value()) {
+    result += fmt::format("  on-enter: {}\n", on_enter.value()->print());
+  } else {
+    result += fmt::format("  on-enter: #f\n");
+  }
+  if (on_inside.has_value()) {
+    result += fmt::format("  on-inside: {}\n", on_inside.value()->print());
+  } else {
+    result += fmt::format("  on-inside: #f\n");
+  }
+  if (on_exit.has_value()) {
+    result += fmt::format("  on-exit: {}\n", on_exit.value()->print());
+  } else {
+    result += fmt::format("  on-exit: #f\n");
+  }
+  return result;
+}
+
+void from_json(const nlohmann::json& json, RegionFaceData& obj) {
+  obj.normal = vector_from_json(json.at("normal"));
+  obj.normal.w() *= METER_LENGTH;
+  std::vector<math::Vector4f> points;
+  for (auto& p : json.at("points")) {
+    points.push_back(vectorm3_from_json(p));
+  }
+  obj.num_points = points.size();
+  obj.points = points;
+}
+
+void from_json(const nlohmann::json& json, RegionFaceArray& obj) {
+  (void)obj;
+  for (const auto& face_json : json.at("faces")) {
+    RegionFaceData face;
+    from_json(face_json, face);
+    obj.faces.push_back(face);
+  }
+}
+
+size_t RegionFaceData::generate(DataObjectGenerator& gen) {
+  size_t result = gen.current_offset_bytes();
+  gen.add_word_float(normal.x());
+  gen.add_word_float(normal.y());
+  gen.add_word_float(normal.z());
+  gen.add_word_float(normal.w());
+  gen.add_word(num_points);
+  gen.add_word(0);
+  gen.add_word(0);
+  gen.add_word(0);
+  for (auto& p : points) {
+    gen.add_word_float(p.x());
+    gen.add_word_float(p.y());
+    gen.add_word_float(p.z());
+    gen.add_word_float(p.w());
+  }
+  return result;
+}
+
+size_t RegionFaceArray::generate(DataObjectGenerator& gen) {
+  gen.align_to_basic();
+  gen.add_type_tag("region-face-array");
+  size_t result = gen.current_offset_bytes();
+  auto length = data.size();
+  gen.add_word(length);
+  gen.add_word(length);
+  gen.add_word(0);
+  for (auto& face : data) {
+    face.generate(gen);
+  }
+  for (int i = 0; i < data.size(); i++) {
+    auto face = data[i];
+    auto face0 = face.data;
+    gen.link_word_to_byte(face.face_data_slot, face0.generate(gen));
+  }
+  return result;
+}
+
+size_t DrawableRegionPrim::generate(DataObjectGenerator& gen) {
+  return 0;
+}
+
+size_t DrawableRegionSphere::generate(DataObjectGenerator& gen) {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-region-sphere");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(region->id);
+  gen.link_word_to_word(gen.add_word(0), region->slot);
+  gen.add_word(0);
+  gen.add_word_float(region->bsphere.x());
+  gen.add_word_float(region->bsphere.y());
+  gen.add_word_float(region->bsphere.z());
+  gen.add_word_float(region->bsphere.w());
+  return result;
+}
+
+size_t DrawableRegionVolume::generate(DataObjectGenerator& gen
+                                      /*size_t region_face_array_slot*/) {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-region-volume");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(region->id);
+  gen.link_word_to_word(gen.add_word(0), region->slot);
+  face_array_slot = gen.add_word(0);
+  gen.add_word_float(region->bsphere.x());
+  gen.add_word_float(region->bsphere.y());
+  gen.add_word_float(region->bsphere.z());
+  gen.add_word_float(region->bsphere.w());
+  return result;
+}
+
+size_t DrawableRegionFace::generate(DataObjectGenerator& gen) {
+  gen.align_to_basic();
+  gen.add_type_tag("drawable-region-face");
+  size_t result = gen.current_offset_bytes();
+  gen.add_word(region->id);
+  gen.link_word_to_word(gen.add_word(0), region->slot);
+  face_data_slot = gen.add_word(0);
+  const auto& bsphere = bsphere_override.has_value() ? bsphere_override.value() : region->bsphere;
+  gen.add_word_float(bsphere.x());
+  gen.add_word_float(bsphere.y());
+  gen.add_word_float(bsphere.z());
+  gen.add_word_float(bsphere.w());
+  return result;
+}
+}  // namespace jak3
diff --git a/goalc/build_level/jak3/Region.h b/goalc/build_level/jak3/Region.h
new file mode 100644
index 0000000000..8c599c9d5f
--- /dev/null
+++ b/goalc/build_level/jak3/Region.h
@@ -0,0 +1,207 @@
+#pragma once
+
+#include <cmath>
+#include <string>
+
+#include "Entity.h"
+
+#include "common/common_types.h"
+#include "common/goos/ParseHelpers.h"
+#include "common/goos/Printer.h"
+#include "common/math/Vector.h"
+
+#include "goalc/data_compiler/DataObjectGenerator.h"
+
+#include "third-party/json.hpp"
+
+namespace jak3 {
+
+struct RegionFaceData {
+  // (normal        vector  :inline  :offset-assert 0)
+  // (normal-offset float            :offset 12)
+  // (num-points    uint32           :offset-assert 16)
+  // (points        vector :inline :dynamic :offset-assert 32) ;; guess
+  math::Vector4f normal;  // w component is normal offset
+  u32 num_points;
+  std::vector<math::Vector4f> points;
+
+  size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+void from_json(const json& j, RegionFaceData& obj);
+
+struct RegionFaceArray;
+
+struct Region {
+  // (id        uint32  :offset-assert 0)
+  // (on-enter  pair    :offset-assert 4)
+  // (on-inside pair    :offset-assert 8)
+  // (on-exit   pair    :offset-assert 12)
+  u32 id;
+  std::optional<goos::Object*> on_enter;
+  std::optional<goos::Object*> on_inside;
+  std::optional<goos::Object*> on_exit;
+  math::Vector4f trans;
+  math::Vector4f bsphere;
+  std::string tree;   // target, camera, data, water, city_vis, sample, light, entity
+  std::string shape;  // sphere, face, volume
+  std::optional<std::vector<RegionFaceData>> faces;
+
+  size_t slot;
+  std::optional<std::map<std::string, size_t>> actor_slots;
+
+  size_t generate(DataObjectGenerator& gen) const;
+  void generate_pairs(DataObjectGenerator& gen, const std::vector<size_t>& pair_slots);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+  std::string print();
+};
+
+struct RegionArray {
+  // (data             region :inline :dynamic :offset-assert 16)
+  std::vector<Region*> data;
+  std::map<int, std::vector<size_t>> pair_slots;
+  std::map<int, size_t> region_slots;
+  std::map<std::string, size_t> entity_actor_slots;
+  std::vector<EntityActor>* entities;
+  std::vector<ActorGroup>* actor_groups;
+
+  size_t slot;
+
+  size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t region_array) const;
+};
+
+struct DrawableRegionPrim {
+  // (deftype drawable-region-prim (drawable)
+  //  ((region region  :offset 8)
+  //   )
+  Region* region;
+
+  explicit DrawableRegionPrim(Region* region) { this->region = region; }
+
+  virtual size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+struct DrawableInlineArrayRegionPrim {
+  // (deftype drawable-inline-array-region-prim (drawable-inline-array)
+  //  ((data drawable-region-prim 1 :inline :offset-assert 32)
+  //  )
+  std::vector<DrawableRegionPrim*> data;
+
+  size_t generate(DataObjectGenerator& gen) const;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+struct DrawableTreeRegionPrim {
+  // (deftype drawable-tree-region-prim (drawable-tree)
+  // ((id      int16  :offset-assert 4)
+  //  (length  int16  :offset 6)
+  //  (name    symbol :offset 8)
+  //  (bsphere vector :inline :offset-assert 16)
+  //  (data2   drawable-inline-array :dynamic :offset 32 :score 1))
+  //  )
+  std::string name;
+  math::Vector4f bsphere;
+  DrawableInlineArrayRegionPrim data2;
+
+  DrawableTreeRegionPrim() = default;
+  explicit DrawableTreeRegionPrim(std::string name_) : name(std::move(name_)) {}
+
+  size_t generate(DataObjectGenerator& gen) const;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+size_t generate_drawable_tree_region_prim_array(DataObjectGenerator& gen,
+                                                RegionArray& regions,
+                                                const std::vector<DrawableTreeRegionPrim>& trees);
+
+void fill_region_trees(std::vector<DrawableTreeRegionPrim>& trees,
+                       std::map<int, Region>& regions,
+                       RegionArray& region_arr,
+                       const nlohmann::json& json,
+                       u32 base_id);
+void add_regions_from_json(const nlohmann::json& json,
+                           DrawableTreeRegionPrim& tree,
+                           std::map<int, Region>& regions,
+                           u32 base_id);
+
+struct DrawableRegionSphere : DrawableRegionPrim {
+  using DrawableRegionPrim::DrawableRegionPrim;
+  size_t generate(DataObjectGenerator& gen) override;
+};
+
+struct DrawableRegionFace : DrawableRegionPrim {
+  // (deftype drawable-region-face (drawable-region-prim)
+  //  ((data region-face-data  :offset 12)
+  //   )
+  RegionFaceData data;
+  size_t face_data_slot;
+  std::optional<math::Vector4f> bsphere_override;
+
+  explicit DrawableRegionFace(Region* region) : DrawableRegionPrim(region) {
+    if (region->faces.has_value()) {
+      data = region->faces.value().at(0);
+    }
+  }
+  size_t generate(DataObjectGenerator& gen) override;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+struct RegionFaceArray {
+  // (deftype region-face-array (inline-array-class)
+  //  ((data drawable-region-face :inline :dynamic :offset 16)
+  //   )
+  std::vector<DrawableRegionFace> data;
+  std::vector<RegionFaceData> faces;
+
+  size_t generate(DataObjectGenerator& gen);
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+
+void from_json(const json& j, RegionFaceArray& obj);
+
+struct DrawableRegionVolume : DrawableRegionPrim {
+  // (deftype drawable-region-volume (drawable-region-prim)
+  //  ((faces region-face-array  :offset 12)
+  //   )
+  RegionFaceArray faces;
+  size_t face_array_slot;
+
+  explicit DrawableRegionVolume(Region* region) : DrawableRegionPrim(region) {
+    if (this->region->faces.has_value()) {
+      auto face_arr = this->region->faces.value();
+      for (const auto& f : face_arr) {
+        auto& face = faces.data.emplace_back(region);
+        face.data = f;
+        // compute per-face bsphere from the face's points for volumes
+        if (!f.points.empty()) {
+          math::Vector4f center = {0, 0, 0, 0};
+          for (auto& pt : f.points) {
+            center.x() += pt.x();
+            center.y() += pt.y();
+            center.z() += pt.z();
+          }
+          auto n = static_cast<float>(f.points.size());
+          center.x() /= n;
+          center.y() /= n;
+          center.z() /= n;
+          float max_dist_sq = 0;
+          for (auto& pt : f.points) {
+            float dx = pt.x() - center.x();
+            float dy = pt.y() - center.y();
+            float dz = pt.z() - center.z();
+            max_dist_sq = std::max(max_dist_sq, dx * dx + dy * dy + dz * dz);
+          }
+          center.w() = std::sqrt(max_dist_sq);
+          face.bsphere_override = center;
+        }
+      }
+    }
+  }
+
+  size_t generate(DataObjectGenerator& gen) override;
+  size_t add_to_object_file(DataObjectGenerator& gen, size_t);
+};
+}  // namespace jak3
\ No newline at end of file
diff --git a/goalc/build_level/jak3/build_level.cpp b/goalc/build_level/jak3/build_level.cpp
index 932ae679ff..781476a8c6 100644
--- a/goalc/build_level/jak3/build_level.cpp
+++ b/goalc/build_level/jak3/build_level.cpp
@@ -7,6 +7,7 @@
 #include "goalc/build_level/jak3/Entity.h"
 #include "goalc/build_level/jak3/FileInfo.h"
 #include "goalc/build_level/jak3/LevelFile.h"
+#include <decompiler/level_extractor/extract_collide_frags.h>
 
 namespace jak3 {
 bool run_build_level(const std::string& input_file,
@@ -58,9 +59,19 @@ bool run_build_level(const std::string& input_file,
              fmt::format("Actor IDs must be unique. Found at least two actors with ID {}",
                          duplicates->aid));
   file.actors = std::move(actors);
+  // actor groups
+  if (level_json.contains("actor_groups") && !level_json.at("actor_groups").empty()) {
+    add_actor_groups_from_json(level_json.at("actor_groups"), file.actors, file.actor_groups, 0);
+  }
   // cameras
   // nodes
   // regions
+  if (level_json.contains("region_trees") && !level_json.at("region_trees").empty()) {
+    file.region_array.entities = &file.actors;
+    file.region_array.actor_groups = &file.actor_groups;
+    fill_region_trees(file.region_trees, file.regions, file.region_array,
+                      level_json.at("region_trees"), level_json.value("base_region_id", 0));
+  }
   // subdivs
   // actor birth
   for (size_t i = 0; i < file.actors.size(); i++) {
@@ -87,6 +98,22 @@ bool run_build_level(const std::string& input_file,
     lg::error("No collision geometry was found");
   } else {
     file.collide_hash = construct_collide_hash(mesh_extract_out.collide.faces);
+    // for collision renderer
+    for (auto& face : mesh_extract_out.collide.faces) {
+      math::Vector4f verts[3];
+      for (int i = 0; i < 3; i++) {
+        verts[i].x() = face.v[i].x();
+        verts[i].y() = face.v[i].y();
+        verts[i].z() = face.v[i].z();
+        verts[i].w() = 1.f;
+      }
+      tfrag3::CollisionMesh::Vertex out_verts[3];
+      decompiler::set_vertices_for_tri(out_verts, verts);
+      for (auto& out : out_verts) {
+        out.pat = face.pat.val;
+        pc_level.collision.vertices.push_back(out);
+      }
+    }
   }
 
   // Save the GOAL level
diff --git a/goalc/data_compiler/DataObjectGenerator.cpp b/goalc/data_compiler/DataObjectGenerator.cpp
index 35f1515df5..6fbf91aeac 100644
--- a/goalc/data_compiler/DataObjectGenerator.cpp
+++ b/goalc/data_compiler/DataObjectGenerator.cpp
@@ -61,6 +61,146 @@ int DataObjectGenerator::add_word_float(float f) {
   return result;
 }
 
+void DataObjectGenerator::add_goos_obj(
+    const goos::Object& obj,
+    const bool last_obj,
+    const std::optional<std::map<std::string, size_t>>& entity_slots,
+    const std::optional<std::map<int, size_t>>& actor_group_slots) {
+  // lg::info("add_goos_obj: {}", obj.inspect());
+  size_t cur_slot = 0;
+  size_t next_slot = 0;
+  if (obj.type == goos::ObjectType::INTEGER || obj.type == goos::ObjectType::FLOAT) {
+    cur_slot = add_word(0);
+    next_slot = add_word(0);
+  }
+  switch (obj.type) {
+    case goos::ObjectType::INTEGER: {
+      add_type_tag("binteger");
+      link_word_to_word(cur_slot, add_word(obj.as_int()));
+    } break;
+    case goos::ObjectType::FLOAT: {
+      add_type_tag("bfloat");
+      link_word_to_word(cur_slot, add_word_float(obj.as_float()));
+    } break;
+    case goos::ObjectType::SYMBOL:
+      add_symbol_link(obj.as_symbol().name_ptr);
+      break;
+    case goos::ObjectType::STRING: {
+      std::string str = obj.as_string()->print();
+      std::erase(str, '\"');
+      add_ref_to_string_in_pool(str);
+    } break;
+    case goos::ObjectType::PAIR: {
+      auto pair_slot = add_word(0);
+      if (last_obj) {
+        add_empty_list();
+      } else {
+        next_slot = add_word(0);
+      }
+      link_word_to_byte(pair_slot, add_pair(obj, entity_slots, actor_group_slots));
+      if (!last_obj) {
+        link_word_to_byte(next_slot, current_offset_bytes() + 2);
+      }
+    } break;
+    default:
+      ASSERT_MSG(false, fmt::format("Unsupported object type in pair: {}", obj.inspect()));
+  }
+  if (!obj.is_pair()) {
+    if (last_obj) {
+      if (obj.type == goos::ObjectType::INTEGER || obj.type == goos::ObjectType::FLOAT) {
+        link_word_to_symbol("_empty_", next_slot);
+      } else {
+        add_empty_list();
+      }
+    } else {
+      if (obj.type == goos::ObjectType::INTEGER || obj.type == goos::ObjectType::FLOAT) {
+        link_word_to_byte(next_slot, current_offset_bytes() + 2);
+      } else {
+        link_word_to_byte(add_word(0), current_offset_bytes() + 2);
+      }
+    }
+  }
+}
+
+int DataObjectGenerator::add_pair(const goos::Object& obj,
+                                  const std::optional<std::map<std::string, size_t>>& entity_slots,
+                                  const std::optional<std::map<int, size_t>>& actor_group_slots) {
+  size_t pair_slot = current_offset_bytes() + 2;
+  // lg::info("add_pair: parsing {}", obj.print());
+
+  goos::Object current = obj;
+  while (!current.is_empty_list()) {
+    // lg::info("add_pair: current {}", current.print());
+    auto next = current.as_pair()->car;
+    // special case for entities or actor groups: script pairs can have references to actor groups
+    // or entities from the level data
+    if (next.is_pair() && next.as_pair()->car.is_symbol()) {
+      if (!strcmp(next.as_pair()->car.as_symbol().name_ptr, "entity-actor")) {
+        if (entity_slots.has_value()) {
+          auto pair = next.as_pair();
+          auto type = pair->car;
+          auto val = pair->cdr.as_pair()->car.as_symbol().name_ptr;
+          auto slot = entity_slots->find(val);
+          if (slot != entity_slots->end()) {
+            link_word_to_byte(add_word(0), slot->second);
+            if (current.as_pair()->cdr.is_empty_list()) {
+              add_empty_list();
+            } else {
+              link_word_to_byte(add_word(0), current_offset_bytes() + 2);
+            }
+          } else {
+            ASSERT_MSG(false, fmt::format("error in pair {}: for {}, entity-actor {} not found",
+                                          obj.print(), pair->print(), val));
+          }
+        }
+      } else if (!strcmp(next.as_pair()->car.as_symbol().name_ptr, "actor-group")) {
+        if (actor_group_slots.has_value()) {
+          auto pair = next.as_pair();
+          auto type = pair->car;
+          auto val = pair->cdr.as_pair()->car.as_int();
+          auto slot = actor_group_slots->find(val);
+          if (slot != actor_group_slots->end()) {
+            link_word_to_byte(add_word(0), slot->second);
+            if (current.as_pair()->cdr.is_empty_list()) {
+              add_empty_list();
+            } else {
+              link_word_to_byte(add_word(0), current_offset_bytes() + 2);
+            }
+          } else {
+            ASSERT_MSG(false, fmt::format("error in pair {}: for {}, got invalid id {}",
+                                          obj.print(), pair->print(), val));
+          }
+        }
+      } else {
+        if (current.as_pair()->cdr.is_empty_list()) {
+          // lg::info("add_pair: next (last elem) {}", next.print());
+          add_goos_obj(next, true, entity_slots, actor_group_slots);
+        } else {
+          // lg::info("add_pair: next {}", next.print());
+          add_goos_obj(next, false, entity_slots, actor_group_slots);
+        }
+      }
+    } else {
+      if (current.as_pair()->cdr.is_empty_list()) {
+        // lg::info("add_pair: next (last elem) {}", next.print());
+        add_goos_obj(next, true, entity_slots, actor_group_slots);
+      } else {
+        // lg::info("add_pair: next {}", next.print());
+        add_goos_obj(next, false, entity_slots, actor_group_slots);
+      }
+    }
+    current = current.as_pair()->cdr;
+  }
+  return pair_slot;
+}
+
+int DataObjectGenerator::add_empty_list() {
+  auto result = int(m_words.size());
+  m_words.push_back(0);
+  m_symbol_links["_empty_"].push_back(result);
+  return result;
+}
+
 void DataObjectGenerator::set_word(u32 word_idx, u32 val) {
   m_words.at(word_idx) = val;
 }
diff --git a/goalc/data_compiler/DataObjectGenerator.h b/goalc/data_compiler/DataObjectGenerator.h
index 5ef2175be0..671d9c1e3b 100644
--- a/goalc/data_compiler/DataObjectGenerator.h
+++ b/goalc/data_compiler/DataObjectGenerator.h
@@ -5,11 +5,21 @@
 #include <vector>
 
 #include "common/common_types.h"
+#include "common/goos/ParseHelpers.h"
+#include "common/log/log.h"
 
 class DataObjectGenerator {
  public:
   int add_word(u32 word);
   int add_word_float(float f);
+  int add_empty_list();
+  void add_goos_obj(const goos::Object& obj,
+                    bool last_obj,
+                    const std::optional<std::map<std::string, size_t>>& entity_slots,
+                    const std::optional<std::map<int, size_t>>& actor_group_slots);
+  int add_pair(const goos::Object& pair,
+               const std::optional<std::map<std::string, size_t>>& entity_slots,
+               const std::optional<std::map<int, size_t>>& actor_group_slots);
   void set_word(u32 word_idx, u32 val);
   void link_word_to_word(int source, int target, int offset = 0);
   void link_word_to_byte(int source_word, int target_byte);