diff --git a/ray_tracing_intersection/hello_vulkan.cpp b/ray_tracing_intersection/hello_vulkan.cpp
index cc4ab8e..fcc46ca 100644
--- a/ray_tracing_intersection/hello_vulkan.cpp
+++ b/ray_tracing_intersection/hello_vulkan.cpp
@@ -720,25 +720,27 @@ nvvk::RaytracingBuilderKHR::Blas HelloVulkan::sphereToVkGeometryKHR()
 //--------------------------------------------------------------------------------------------------
 // Creating all spheres
 //
-void HelloVulkan::createSpheres()
+void HelloVulkan::createSpheres(uint32_t nbSpheres)
 {
   std::random_device                    rd{};
   std::mt19937                          gen{rd()};
   std::normal_distribution<float>       xzd{0.f, 5.f};
-  std::normal_distribution<float>       yd{3.f, 1.f};
+  std::normal_distribution<float>       yd{6.f, 3.f};
   std::uniform_real_distribution<float> radd{.05f, .2f};
 
   // All spheres
   Sphere s;
-  for(uint32_t i = 0; i < 2000000; i++)
+  m_spheres.resize(nbSpheres);
+  for(uint32_t i = 0; i < nbSpheres; i++)
   {
-    s.center = nvmath::vec3f(xzd(gen), yd(gen), xzd(gen));
-    s.radius = radd(gen);
-    m_spheres.emplace_back(s);
+    s.center     = nvmath::vec3f(xzd(gen), yd(gen), xzd(gen));
+    s.radius     = radd(gen);
+    m_spheres[i] = std::move(s);
   }
 
   // Axis aligned bounding box of each sphere
   std::vector<Aabb> aabbs;
+  aabbs.reserve(nbSpheres);
   for(const auto& s : m_spheres)
   {
     Aabb aabb;
@@ -751,7 +753,7 @@ void HelloVulkan::createSpheres()
   MaterialObj mat;
   mat.diffuse = vec3f(0, 1, 1);
   std::vector<MaterialObj> materials;
-  std::vector<int>         matIdx;
+  std::vector<int>         matIdx(nbSpheres);
   materials.emplace_back(mat);
   mat.diffuse = vec3f(1, 1, 0);
   materials.emplace_back(mat);
@@ -759,7 +761,7 @@ void HelloVulkan::createSpheres()
   // Assign a material to each sphere
   for(size_t i = 0; i < m_spheres.size(); i++)
   {
-    matIdx.push_back(i % 2);
+    matIdx[i] = i % 2;
   }
 
   // Creating all buffers
diff --git a/ray_tracing_intersection/hello_vulkan.h b/ray_tracing_intersection/hello_vulkan.h
index fd35851..0521ea6 100644
--- a/ray_tracing_intersection/hello_vulkan.h
+++ b/ray_tracing_intersection/hello_vulkan.h
@@ -85,9 +85,9 @@ public:
   // Information pushed at each draw call
   struct ObjPushConstant
   {
-    nvmath::vec3f lightPosition{10.f, 15.f, 8.f};
+    nvmath::vec3f lightPosition{10.f, 55.f, 8.f};
     int           instanceId{0};  // To retrieve the transformation matrix
-    float         lightIntensity{100.f};
+    float         lightIntensity{1000.f};
     int           lightType{0};  // 0: point, 1: infinite
   };
   ObjPushConstant m_pushConstant;
@@ -182,5 +182,5 @@ public:
   nvvk::Buffer        m_spheresAabbBuffer;      // Buffer of all Aabb
   nvvk::Buffer        m_spheresMatColorBuffer;  // Multiple materials
   nvvk::Buffer        m_spheresMatIndexBuffer;  // Define which sphere uses which material
-  void                createSpheres();
+  void                createSpheres(uint32_t nbSpheres);
 };
diff --git a/ray_tracing_intersection/main.cpp b/ray_tracing_intersection/main.cpp
index 3dbaba0..115103a 100644
--- a/ray_tracing_intersection/main.cpp
+++ b/ray_tracing_intersection/main.cpp
@@ -69,11 +69,12 @@ void renderUI(HelloVulkan& helloVk)
     up = nvmath::vec3f(item == 0, item == 1, item == 2);
     CameraManip.setLookat(pos, eye, up);
   }
-  ImGui::SliderFloat3("Light Position", &helloVk.m_pushConstant.lightPosition.x, -20.f, 20.f);
-  ImGui::SliderFloat("Light Intensity", &helloVk.m_pushConstant.lightIntensity, 0.f, 100.f);
+  ImGui::SliderFloat3("Light Position", &helloVk.m_pushConstant.lightPosition.x, -200.f, 200.f);
+  ImGui::SliderFloat("Light Intensity", &helloVk.m_pushConstant.lightIntensity, 0.f, 1000.f);
   ImGui::RadioButton("Point", &helloVk.m_pushConstant.lightType, 0);
   ImGui::SameLine();
   ImGui::RadioButton("Infinite", &helloVk.m_pushConstant.lightType, 1);
+  ImGui::Text("Nb Spheres and Cubes: %d", helloVk.m_spheres.size());
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -177,7 +178,7 @@ int main(int argc, char** argv)
   // Creation of the example
   //  helloVk.loadModel(nvh::findFile("media/scenes/Medieval_building.obj", defaultSearchPaths));
   helloVk.loadModel(nvh::findFile("media/scenes/plane.obj", defaultSearchPaths));
-  helloVk.createSpheres();
+  helloVk.createSpheres(2000000);
 
   helloVk.createOffscreenRender();
   helloVk.createDescriptorSetLayout();