diff --git a/assignment-1d/.gitignore b/assignment-1d/.gitignore
index 38a241f..59b392f 100644
--- a/assignment-1d/.gitignore
+++ b/assignment-1d/.gitignore
@@ -8,3 +8,4 @@
 perf.data*
 flamegraph.svg
 showcase.png
+/out.log
diff --git a/assignment-1d/src/scene/illumination.rs b/assignment-1d/src/scene/illumination.rs
index fc8bfcf..7972b68 100644
--- a/assignment-1d/src/scene/illumination.rs
+++ b/assignment-1d/src/scene/illumination.rs
@@ -18,9 +18,14 @@ use super::{
 
 // TODO: Is this a good constant?
 const JITTER_CONST: f64 = 0.05;
-
 const ZERO_COLOR: Color = Color::new(0.0, 0.0, 0.0);
 
+// Soft shadows: jitter some rays here to somewhere close to the
+// actual location as well, and measure the proportion
+// of them that intersect any objects
+const SOFT_SHADOW_JITTER_RADIUS: f64 = 1.0;
+const JITTER_RAYS: usize = 75;
+
 impl Scene {
   /// Determine the color that should be used to fill this pixel.
   ///
@@ -218,6 +223,12 @@ impl Scene {
       .enumerate()
       .filter(|(i, _)| *i != obj_idx);
 
+    #[derive(Clone, Copy)]
+    struct ShadowResult {
+      transparent_coefficient: f64,
+      opacity: f64,
+    }
+
     // Get the list of intersections with all the other objects in the scene
     // This list will be a set of opacities
     let intersections = other_objects
@@ -243,7 +254,13 @@ impl Scene {
             } else {
               let soft_shadow_coefficient =
                 self.compute_soft_shadow_coefficient(location, point, object);
-              Some(soft_shadow_coefficient)
+
+              let material = &self.materials[object.material_idx];
+
+              Some(ShadowResult {
+                transparent_coefficient: 1.0 - material.alpha,
+                opacity: soft_shadow_coefficient,
+              })
             }
           }
 
@@ -253,7 +270,10 @@ impl Scene {
             if intersection_time <= 0.0 {
               None
             } else {
-              Some(0.0) // complete obstruction
+              Some(ShadowResult {
+                transparent_coefficient: 1.0,
+                opacity: 0.0,
+              }) // complete obstruction
             }
           }
         }
@@ -263,9 +283,15 @@ impl Scene {
     match intersections.is_empty() {
       true => 1.0,
       false => {
-        let average = intersections.iter().cloned().sum::<f64>()
+        let average = intersections.iter().map(|s| s.opacity).sum::<f64>()
           / intersections.len() as f64;
-        average
+
+        let transparency = intersections
+          .iter()
+          .map(|s| s.transparent_coefficient)
+          .product::<f64>();
+
+        average * transparency
       }
     }
   }
@@ -276,22 +302,17 @@ impl Scene {
     original_intersection_point: Point,
     object: &Object,
   ) -> f64 {
-    // Soft shadows: jitter some rays here to somewhere close to the
-    // actual location as well, and measure the proportion
-    // of them that intersect any objects
-    const JITTER_RADIUS: f64 = 1.0;
-    const JITTER_RAYS: usize = 75;
-
     let mut rng = rand::thread_rng();
     let locations = iter::repeat_with(|| {
-      let x = rng.gen_range(0.0..JITTER_RADIUS);
-      let y = rng.gen_range(0.0..JITTER_RADIUS);
-      let z = rng.gen_range(0.0..JITTER_RADIUS);
+      let x = rng.gen_range(0.0..SOFT_SHADOW_JITTER_RADIUS);
+      let y = rng.gen_range(0.0..SOFT_SHADOW_JITTER_RADIUS);
+      let z = rng.gen_range(0.0..SOFT_SHADOW_JITTER_RADIUS);
       let delta = Vector::new(x, y, z);
       light_location + delta
     })
     .take(JITTER_RAYS)
     .collect::<Vec<_>>();
+
     let num_obstructed_rays = locations
       .into_par_iter()
       .filter(|location| {
@@ -431,14 +452,14 @@ impl Scene {
     let t_lambda = self.trace_single_ray(ray, depth + 1)?;
 
     let value = (1.0 - fresnel_coefficient) * (1.0 - material.alpha) * t_lambda;
-    debug!(
+    /* debug!(
       depth,
       fresnel_coefficient,
       alpha = material.alpha,
       ?t_lambda,
       ?value,
       "computing final value"
-    );
+    ); */
 
     Ok(value)
   }
diff --git a/assignment-1d/src/scene/sphere.rs b/assignment-1d/src/scene/sphere.rs
index 7805e8f..e828840 100644
--- a/assignment-1d/src/scene/sphere.rs
+++ b/assignment-1d/src/scene/sphere.rs
@@ -81,7 +81,7 @@ impl Sphere {
       let dy = ray.origin.y - self.center.y;
       let dz = ray.origin.z - self.center.z;
 
-      dx.powi(2) + dy.powi(2) + dz.powi(2) < self.radius.powi(2)
+      dx.powi(2) + dy.powi(2) + dz.powi(2) <= self.radius.powi(2)
     };
 
     /* let normal = match exiting {