diff --git a/Assignments/Assignment1/Application1.cpp b/Assignments/Assignment1/Application1.cpp
index 113b053..2c8a86d 100644
--- a/Assignments/Assignment1/Application1.cpp
+++ b/Assignments/Assignment1/Application1.cpp
@@ -6,6 +6,8 @@
 #include "ray.hpp"
 #include "sampling.hpp"
 
+#define EPS 0.1f
+
 void Application1::initScene() {
     Data_Constructor(&data, 1, 8);
 
@@ -70,14 +72,109 @@ void Application1::veachScene() {
 
 Vec3fa Application1::renderPixel(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
     if (selected == 0) {
-    return renderPixelOrig(x, y, camera, stats, sampler);
+        return renderPixelOrig(x, y, camera, stats, sampler);
     } else if (selected == 1) {
         return renderPixelPathTracer(x, y, camera, stats, sampler);
+    } else if (selected == 2) {
+        return renderPixelNextEventEstimation(x, y, camera, stats, sampler);
     } else {
         return Vec3fa(0.0f);
     }
 }
 
+Vec3fa Application1::renderPixelNextEventEstimation(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
+    /* radiance accumulator and weight */
+    Vec3fa L = Vec3fa(0.0f);
+    Vec3fa Lw = Vec3fa(1.0f);
+
+    /* initialize ray */
+    Ray ray(Vec3fa(camera.xfm.p), Vec3fa(normalize(x * camera.xfm.l.vx + y * camera.xfm.l.vy + camera.xfm.l.vz)), 0.0f,
+            inf);
+
+
+    for (int i = 0; i < ray_depth; i++) {
+        /* intersect ray with scene */
+        RTCIntersectArguments iargs;
+        rtcInitIntersectArguments(&iargs);
+        iargs.feature_mask = RTC_FEATURE_FLAG_TRIANGLE;
+        rtcIntersect1(data.g_scene, RTCRayHit_(ray), &iargs);
+        RayStats_addRay(stats);
+
+        const Vec3fa wo = neg(ray.dir);
+
+        /* shade pixels */
+        if (ray.geomID == RTC_INVALID_GEOMETRY_ID) {
+            break;
+        }
+
+        
+        Vec3fa Ns = normalize(ray.Ng);
+        Sample sample;
+        sample.P = ray.org + ray.tfar * ray.dir;
+        sample.Ng = ray.Ng;
+        sample.Ns = Ns;
+        int matId = data.scene->geometries[ray.geomID]->materialID;
+        unsigned lightID = data.scene->geometries[ray.geomID]->lightID;
+        sample.Ng = face_forward(ray.dir, normalize(sample.Ng));
+        sample.Ns = face_forward(ray.dir, normalize(sample.Ns));
+
+        if (lightID != unsigned(-1)) {
+            if (i == 0) {
+                const Light* l = data.scene->lights[lightID];
+                Light_EvalRes evalRes = Lights_eval(l, sample, -wo);
+                L += Lw * evalRes.value * dot(sample.Ng, -ray.dir);
+            }
+            break;
+        }
+
+        /* calculate BRDF */
+        BRDF brdf;
+        std::vector<Material *> material_array = data.scene->materials;
+        Material__preprocess(material_array, matId, brdf, wo, sample);
+
+        /* Light ray  */
+        int id = (int)(RandomSampler_get1D(sampler) * data.scene->lights.size());
+        if (id == data.scene->lights.size())
+            id = data.scene->lights.size() - 1;
+        const Light* l = data.scene->lights[id];
+
+        Light_SampleRes ls = Lights_sample(l, sample, RandomSampler_get2D(sampler));
+
+        Vec3fa light_diffuse = Material__eval(material_array, matId, brdf, wo, sample, ls.dir);
+
+        /* initialize shadow ray */
+        Ray shadow(sample.P, ls.dir, EPS, ls.dist - EPS, 0.0f);
+
+        /* trace shadow ray */
+        RTCOccludedArguments sargs;
+        rtcInitOccludedArguments(&sargs);
+        sargs.feature_mask = RTC_FEATURE_FLAG_TRIANGLE;
+        rtcOccluded1(data.g_scene, RTCRay_(shadow), &sargs);
+        RayStats_addShadowRay(stats);
+
+        /* add light contribution if not occluded */
+        if (shadow.tfar >= 0.0f) {
+            // L += Lw * light_diffuse * ls.weight;
+            L += Lw * light_diffuse * ls.weight * dot(sample.Ng, ls.dir) / data.scene->lights.size();
+        }
+
+            
+        /* sample BRDF at hit point */
+        Vec2f uv = RandomSampler_get2D(sampler);
+        Sample3f wi;
+        
+        Vec3fa diffuse = Material__sample(material_array, matId, brdf, Lw, wo, sample, wi, uv);
+
+        Lw *= M_PI * diffuse;
+
+        ray = Ray(sample.P,wi.v, EPS,inf);
+
+    }
+
+    return L;
+}
+
+
 Vec3fa Application1::renderPixelPathTracer(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
     /* radiance accumulator and weight */
     Vec3fa L = Vec3fa(0.0f);
@@ -117,7 +214,7 @@ Vec3fa Application1::renderPixelPathTracer(float x, float y, const ISPCCamera& c
         if (lightID != unsigned(-1)) {
             const Light* l = data.scene->lights[lightID];
             Light_EvalRes evalRes = Lights_eval(l, sample, -wo);
-            L += Lw * evalRes.value;
+            return Lw * evalRes.value * dot(wo, sample.Ng);
             break;
         }
 
@@ -129,13 +226,13 @@ Vec3fa Application1::renderPixelPathTracer(float x, float y, const ISPCCamera& c
         /* sample BRDF at hit point */
 
         Vec2f uv = RandomSampler_get2D(sampler);
-        Sample3f wi = cosineSampleHemisphere(uv.x, uv.y, sample.Ng);
+        Sample3f wi;
         
-        Vec3fa diffuse = Material__eval(material_array, matId, brdf, wo, sample, wi.v);
+        Vec3fa diffuse = Material__sample(material_array, matId, brdf, Lw, wo, sample, wi, uv);
 
         Lw *= M_PI * diffuse;
 
-        ray = Ray(sample.P,wi.v,0.1,inf);
+        ray = Ray(sample.P,wi.v,EPS,inf);
 
     }
 
@@ -199,7 +296,7 @@ Vec3fa Application1::renderPixelOrig(float x, float y, const ISPCCamera& camera,
             Vec3fa diffuse = Material__eval(material_array, matId, brdf, wo, sample, ls.dir);
 
             /* initialize shadow ray */
-            Ray shadow(sample.P, ls.dir, 0.001f, ls.dist, 0.0f);
+            Ray shadow(sample.P, ls.dir, EPS, ls.dist - EPS, 0.0f);
 
             /* trace shadow ray */
             RTCOccludedArguments sargs;
diff --git a/Assignments/Assignment1/Application1.h b/Assignments/Assignment1/Application1.h
index eddaa5e..96f3f9b 100644
--- a/Assignments/Assignment1/Application1.h
+++ b/Assignments/Assignment1/Application1.h
@@ -12,6 +12,7 @@ private:
     Vec3fa renderPixel(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) override;
     Vec3fa renderPixelOrig(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
     Vec3fa renderPixelPathTracer(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
+    Vec3fa renderPixelNextEventEstimation(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
 
     void drawGUI() override {
         ImGui::ColorEdit3("Color", colorLight);
@@ -20,8 +21,8 @@ private:
             ray_depth = 1;
         }
 
-        const char* items[] = {"Original", "Path Tracer"};
-        ImGui::Combo("Version", &selected, items, 2);
+        const char* items[] = {"Original", "Path Tracer", "Next Event Estimation"};
+        ImGui::Combo("Version", &selected, items, 3);
         
         const char* scenes[] = {"Cornell", "Veach"};
         int oldscene = scene;
diff --git a/Framework/include/scene.hpp b/Framework/include/scene.hpp
index 13c6b4f..9c66ff0 100644
--- a/Framework/include/scene.hpp
+++ b/Framework/include/scene.hpp
@@ -253,7 +253,7 @@ struct RenderScene {
         else if (auto light = in.dynamicCast<SceneGraph::LightNodeImpl<SceneGraph::PointLight> >())
             PointLight_set(out, light->light.P, light->light.I, 0.f);
         else if (auto light = in.dynamicCast<SceneGraph::LightNodeImpl<SceneGraph::QuadLight> >())
-            QuadLight_set(out, light->light.v0,light->light.v1-light->light.v0,light->light.v2-light->light.v0,light->light.L);
+            QuadLight_set(out, light->light.v0,light->light.v3-light->light.v0,light->light.v2-light->light.v0,light->light.L);
     }
 
     RTCScene scene;