diff --git a/include/3d/AABB.cuh b/include/3d/AABB.cuh
index 6cc3431..9019876 100644
--- a/include/3d/AABB.cuh
+++ b/include/3d/AABB.cuh
@@ -12,6 +12,7 @@ public:
   __device__ AABB();
   __device__ AABB(const Interval &_x, const Interval &_y, const Interval &_z);
   __device__ AABB(const Point3 &a, const Point3 &b);
+  __device__ AABB(const AABB &box1, const AABB &box2);
 
   __device__ const Interval &axis(int i) const;
   __device__ bool hit(const Ray &r, Interval ray_t) const;
diff --git a/include/3d/Scene.cuh b/include/3d/Scene.cuh
index f7727c1..546809b 100644
--- a/include/3d/Scene.cuh
+++ b/include/3d/Scene.cuh
@@ -8,10 +8,10 @@
 
 class Scene : public Object {
 public:
-  Object **_objects;
-  int _num_objects = 0;
+  Object **objects;
+  int count = 0;
 
-  __device__ Scene(Object **objects, int num_objects);
+  __device__ Scene(Object **objects, int numobjects);
 
   // __device__ void add(Object *object);
 
diff --git a/include/math/Interval.cuh b/include/math/Interval.cuh
index 4b7860a..e838013 100644
--- a/include/math/Interval.cuh
+++ b/include/math/Interval.cuh
@@ -8,19 +8,16 @@ public:
   float min;
   float max;
 
-  __host__ __device__ Interval() : min(+infinity), max(-infinity) {}
+  __device__ Interval() : min(+infinity), max(-infinity) {}
+  __device__ Interval(float min, float max) : min(min), max(max) {}
+  __device__ Interval(const Interval &a, const Interval &b)
+      : min(fmin(a.min, b.min)), max(fmax(a.max, b.max)) {}
 
-  __host__ __device__ Interval(float min, float max) : min(min), max(max) {}
+  __device__ bool contains(float x) const { return min <= x && x <= max; }
 
-  __host__ __device__ bool contains(float x) const {
-    return min <= x && x <= max;
-  }
-
-  __host__ __device__ bool surrounds(float x) const {
-    return min < x && x < max;
-  }
+  __device__ bool surrounds(float x) const { return min < x && x < max; }
 
-  __host__ __device__ float clamp(float x) const {
+  __device__ float clamp(float x) const {
     if (x < min)
       return min;
 
diff --git a/src/3d/AABB.cu b/src/3d/AABB.cu
index fa6f80b..6e8495b 100644
--- a/src/3d/AABB.cu
+++ b/src/3d/AABB.cu
@@ -11,6 +11,11 @@ __device__ AABB::AABB(const Point3 &a, const Point3 &b) {
   y = Interval(fmin(a.y, b.y), fmax(a.y, b.y));
   z = Interval(fmin(a.z, b.z), fmax(a.z, b.z));
 }
+__device__ AABB::AABB(const AABB &a, const AABB &b) {
+  x = Interval(a.x, b.x);
+  y = Interval(a.y, b.y);
+  z = Interval(a.z, b.z);
+}
 
 __device__ const Interval &AABB::axis(int i) const {
   if (i == 0)
diff --git a/src/3d/Scene.cu b/src/3d/Scene.cu
index d6d3f50..3a22207 100644
--- a/src/3d/Scene.cu
+++ b/src/3d/Scene.cu
@@ -1,11 +1,11 @@
 #include "Scene.cuh"
 #include "cuda_helper.cuh"
 
-__device__ Scene::Scene(Object **objects, int num_objects)
-    : _objects(objects), _num_objects(num_objects) {}
+__device__ Scene::Scene(Object **objects, int numobjects)
+    : objects(objects), count(numobjects) {}
 
 // __device__ void Scene::add(Object *object) {
-//   *(d_objects + _num_objects++) = object;
+//   *(dobjects + count++) = object;
 // }
 
 __device__ bool Scene::hit(const Ray &ray, float t_min, float t_max,
@@ -14,8 +14,8 @@ __device__ bool Scene::hit(const Ray &ray, float t_min, float t_max,
   bool hit_anything = false;
   float closest_so_far = t_max;
 
-  for (int i = 0; i < _num_objects; i++) {
-    bool got_hit = _objects[i]->hit(ray, t_min, t_max, temp_record);
+  for (int i = 0; i < count; i++) {
+    bool got_hit = objects[i]->hit(ray, t_min, t_max, temp_record);
 
     if (got_hit && temp_record.t < closest_so_far) {
       hit_anything = true;
@@ -27,4 +27,11 @@ __device__ bool Scene::hit(const Ray &ray, float t_min, float t_max,
   return hit_anything;
 }
 
-__device__ void Scene::computeBoundingBox() { return; }
+__device__ void Scene::computeBoundingBox() {
+  boundingBox = AABB();
+
+  for (int i = 0; i < count; i++) {
+    objects[i]->computeBoundingBox();
+    boundingBox = AABB(boundingBox, objects[i]->boundingBox);
+  }
+}