diff --git a/i-mic-fps.rb b/i-mic-fps.rb
index 734790f..d8b3e16 100644
--- a/i-mic-fps.rb
+++ b/i-mic-fps.rb
@@ -37,8 +37,6 @@ else
   raise RuntimeError, "Unsupported platform."
 end
 
-BoundingBox = Struct.new(:min_x, :min_y, :min_z, :max_x, :max_y, :max_z)
-
 if RUBY_VERSION < "2.5.0"
   puts "-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-"
   puts "|NOTICE| Ruby is #{RUBY_VERSION} not 2.5.0+..............................|Notice|"
@@ -63,6 +61,7 @@ $debug = ARGV.join.include?("--debug") ? true : false
 require_relative "lib/common_methods"
 
 require_relative "lib/math/vector"
+require_relative "lib/math/bounding_box"
 require_relative "lib/trees/aabb_tree"
 
 require_relative "lib/managers/input_mapper"
diff --git a/lib/managers/collision_manager.rb b/lib/managers/collision_manager.rb
index b948ca7..9ecbb30 100644
--- a/lib/managers/collision_manager.rb
+++ b/lib/managers/collision_manager.rb
@@ -9,6 +9,11 @@ class IMICFPS
       @aabb_tree.add(entity.normalized_bounding_box, entity)
     end
 
+    def update
+      lazy_check_collisions
+      @aabb_tree.update
+    end
+
     def remove(entity)
       @aabb_tree.remove(entity)
     end
@@ -19,8 +24,10 @@ class IMICFPS
         @game_state.entities.each do |other|
           next if entity == other
           next if entity.is_a?(Terrain) || other.is_a?(Terrain)
+          next unless entity.collidable?
+          next unless other.collidable?
 
-          if entity.intersect(other)
+          if entity.normalized_bounding_box.intersect(other.normalized_bounding_box)
             entity.debug_color = Color.new(1.0,0.0,0.0)
             other.debug_color = Color.new(1.0,0.0,0.0)
 
@@ -33,10 +40,5 @@ class IMICFPS
         end
       end
     end
-
-    def update
-      lazy_check_collisions
-      # @aabb_tree.rebuild
-    end
   end
 end
diff --git a/lib/math/bounding_box.rb b/lib/math/bounding_box.rb
new file mode 100644
index 0000000..27e4d42
--- /dev/null
+++ b/lib/math/bounding_box.rb
@@ -0,0 +1,100 @@
+class IMICFPS
+  class BoundingBox
+    attr_accessor :min_x, :min_y, :min_z, :max_x, :max_y, :max_z
+
+    def initialize(min_x = 0.0, min_y = 0.0, min_z = 0.0, max_x = 0.0, max_y = 0.0, max_z = 0.0)
+      @min_x = min_x
+      @min_y = min_y
+      @min_z = min_z
+
+      @max_x = max_x
+      @max_y = max_y
+      @max_z = max_z
+    end
+
+    def ==(other)
+      min_x == other.min_x &&
+      min_y == other.min_y &&
+      min_z == other.min_z &&
+      max_x == other.max_x &&
+      max_y == other.max_y &&
+      max_z == other.max_z
+    end
+
+    # returns a new bounding box that includes both bounding boxes
+    def union(other)
+      temp = BoundingBox.new
+      temp.min_x = [min_x, other.min_x].min
+      temp.min_y = [min_y, other.min_y].min
+      temp.min_z = [min_z, other.min_z].min
+
+      temp.max_x = [max_x, other.max_x].max
+      temp.max_y = [max_y, other.max_y].max
+      temp.max_z = [max_z, other.max_z].max
+
+      return temp
+    end
+
+    # returns boolean
+    def intersect(other)
+      (min_x <= other.max_x && max_x >= other.min_x) &&
+      (min_y <= other.max_y && max_y >= other.min_y) &&
+      (min_z <= other.max_z && max_z >= other.min_z)
+    end
+
+    def difference(other)
+      temp = BoundingBox.new
+      temp.min_x = min_x - other.min_x
+      temp.min_y = min_y - other.min_y
+      temp.min_z = min_z - other.min_z
+
+      temp.max_x = max_x - other.max_x
+      temp.max_y = max_y - other.max_y
+      temp.max_z = max_z - other.max_z
+
+      return temp
+    end
+
+    def volume
+      width * height * depth
+    end
+
+    def width
+      @max_x - @min_x
+    end
+
+    def height
+      @max_y - @min_y
+    end
+
+    def depth
+      @max_z - @min_z
+    end
+
+    def normalize(entity)
+      temp = BoundingBox.new
+      temp.min_x = min_x.to_f * entity.scale
+      temp.min_y = min_y.to_f * entity.scale
+      temp.min_z = min_z.to_f * entity.scale
+
+      temp.max_x = max_x.to_f * entity.scale
+      temp.max_y = max_y.to_f * entity.scale
+      temp.max_z = max_z.to_f * entity.scale
+
+      return temp
+    end
+
+    def normalize_with_offset(entity)
+      temp = BoundingBox.new
+      temp.min_x = min_x.to_f * entity.scale + entity.position.x
+      temp.min_y = min_y.to_f * entity.scale + entity.position.y
+      temp.min_z = min_z.to_f * entity.scale + entity.position.z
+
+      temp.max_x = max_x.to_f * entity.scale + entity.position.x
+      temp.max_y = max_y.to_f * entity.scale + entity.position.y
+      temp.max_z = max_z.to_f * entity.scale + entity.position.z
+
+      return temp
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/objects/entities/terrain.rb b/lib/objects/entities/terrain.rb
index 63abbaa..d8404b4 100644
--- a/lib/objects/entities/terrain.rb
+++ b/lib/objects/entities/terrain.rb
@@ -1,7 +1,7 @@
 class IMICFPS
   class Terrain < Entity
     def setup
-      bind_model("base", "randomish_terrain")
+       bind_model("base", "randomish_terrain")
     end
   end
 end
\ No newline at end of file
diff --git a/lib/objects/entity.rb b/lib/objects/entity.rb
index cdbd5a8..f7901dc 100644
--- a/lib/objects/entity.rb
+++ b/lib/objects/entity.rb
@@ -6,10 +6,9 @@ class IMICFPS
     include OpenGL
     include GLU
     include CommonMethods
-    attr_accessor :scale
-    attr_accessor :visible, :renderable, :backface_culling
+    attr_accessor :scale, :visible, :renderable, :backface_culling
     attr_reader :position, :rotation, :velocity
-    attr_reader :model, :name, :debug_color, :width, :height, :depth, :last_x, :last_y, :last_z, :normalized_bounding_box
+    attr_reader :model, :name, :debug_color, :normalized_bounding_box
     def initialize(x: 0, y: 0, z: 0, bound_model: nil, scale: MODEL_METER_SCALE, backface_culling: true, auto_manage: true, manifest_file: nil)
       @position = Vector.new(x, y, z)
       @scale = scale
@@ -27,7 +26,6 @@ class IMICFPS
       @physics    = false
       @mass       = 100 # kg
 
-      @width, @height, @depth = 0,0,0
       @delta_time = Gosu.milliseconds
       @last_position = Vector.new(@position.x, @position.y, @position.z)
 
@@ -39,9 +37,6 @@ class IMICFPS
         @normalized_bounding_box = normalize_bounding_box_with_offset
 
         box = normalize_bounding_box
-        @width  = box.max_x-box.min_x
-        @height = box.max_y-box.min_y
-        @depth  = box.max_z-box.min_z
       end
 
       return self
@@ -61,9 +56,6 @@ class IMICFPS
       @normalized_bounding_box = normalize_bounding_box_with_offset
 
       box = normalize_bounding_box
-      @width  = box.max_x-box.min_x
-      @height = box.max_y-box.min_y
-      @depth  = box.max_z-box.min_z
     end
 
     def model
@@ -89,8 +81,6 @@ class IMICFPS
       unless at_same_position?
         @normalized_bounding_box = normalize_bounding_box_with_offset if model
       end
-
-      @last_x, @last_y, @last_z = @x, @y, @z
     end
 
     def debug_color=(color)
@@ -101,53 +91,16 @@ class IMICFPS
       @position == @last_position
     end
 
-    # Do two Axis Aligned Bounding Boxes intersect?
-    def intersect(other)
-      me = normalized_bounding_box
-      other = other.normalized_bounding_box
-
-      # puts "bounding boxes match!" if a == b
-      if  (me.min_x <= other.max_x && me.max_x >= other.min_x) &&
-          (me.min_y <= other.max_y && me.max_y >= other.min_y) &&
-          (me.min_z <= other.max_z && me.max_z >= other.min_z)
-        return true
-      else
-        return false
-      end
-    end
-
     def distance(vertex, other)
       return Math.sqrt((vertex.x-other.x)**2 + (vertex.y-other.y)**2 + (vertex.z-other.z)**2)
     end
 
-    def normalize_bounding_box
-      box = @bound_model.model.bounding_box
-
-      temp = BoundingBox.new
-      temp.min_x = box.min_x.to_f*scale
-      temp.min_y = box.min_y.to_f*scale
-      temp.min_z = box.min_z.to_f*scale
-
-      temp.max_x = box.max_x.to_f*scale
-      temp.max_y = box.max_y.to_f*scale
-      temp.max_z = box.max_z.to_f*scale
-
-      return temp
+    def normalize_bounding_box_with_offset
+      @bound_model.model.bounding_box.normalize_with_offset(self)
     end
 
-    def normalize_bounding_box_with_offset
-      box = @bound_model.model.bounding_box
-
-      temp = BoundingBox.new
-      temp.min_x = box.min_x.to_f*scale+@position.x
-      temp.min_y = box.min_y.to_f*scale+@position.y
-      temp.min_z = box.min_z.to_f*scale+@position.z
-
-      temp.max_x = box.max_x.to_f*scale+@position.x
-      temp.max_y = box.max_y.to_f*scale+@position.y
-      temp.max_z = box.max_z.to_f*scale+@position.z
-
-      return temp
+    def normalize_bounding_box
+      @bound_model.model.bounding_box.normalize(self)
     end
 
     def handleGlError
diff --git a/lib/trees/aabb_tree.rb b/lib/trees/aabb_tree.rb
index 0f83bf2..ef907b8 100644
--- a/lib/trees/aabb_tree.rb
+++ b/lib/trees/aabb_tree.rb
@@ -10,13 +10,20 @@ class IMICFPS
       raise "Object can't be nil!" unless object
 
       if @root
-        @root.insert_subtree(bounding_box, object)
+        @root.insert_subtree(bounding_box.dup, object)
       else
         @root = AABBNode.new(parent: nil, object: object, bounding_box: BoundingBox.new(0,0,0, 0,0,0))
       end
     end
 
-    def update(object)
+    def update
+      @objects.each do |object, node|
+        unless object.bounding_box == node.bounding_box
+          puts "#{object.class} mutated!"
+          remove(node)
+          add(object)
+        end
+      end
     end
 
     # Returns a list of all collided objects inside Bounding Box
@@ -26,17 +33,23 @@ class IMICFPS
     end
 
     def remove(object)
+      @root.remove_subtree(@objects[object])
+      @objects[object] = nil
     end
 
     class AABBNode
+      attr_accessor :bounding_box, :parent, :object, :a, :b
       def initialize(parent:, object:, bounding_box:)
         @parent = parent
         @object = object
         @bounding_box = bounding_box
+
+        @a = nil
+        @b = nil
       end
 
       def insert_subtree(bounding_box, object)
-        p "#{bounding_box} -> #{object.class}"
+        # p "#{bounding_box} -> #{object.class}"
       end
 
       def remove_subtree(node)