diff --git a/cs658/final/util/Ray.cc b/cs658/final/util/Ray.cc
index ba1f2a0..5a6ba72 100644
--- a/cs658/final/util/Ray.cc
+++ b/cs658/final/util/Ray.cc
@@ -10,3 +10,16 @@ Ray::Ray(const Vector & origin, const Vector & direction)
     m_origin = origin;
     m_direction = direction;
 }
+
+/*
+ * return a vector for the point at distance dist
+ * from the ray's origin point, along its direction.
+ */
+Vector Ray::getPositionAt(double dist) const
+{
+    Vector v;
+    v[0] = m_origin[0] + dist * m_direction[0];
+    v[1] = m_origin[1] + dist * m_direction[1];
+    v[2] = m_origin[2] + dist * m_direction[2];
+    return v;
+}
diff --git a/cs658/final/util/Ray.h b/cs658/final/util/Ray.h
index 93b5ff0..85367fd 100644
--- a/cs658/final/util/Ray.h
+++ b/cs658/final/util/Ray.h
@@ -11,6 +11,7 @@ class Ray
         Ray(const Vector & origin, const Vector & direction);
         Vector getOrigin() const { return m_origin; }
         Vector getDirection() const { return m_direction; }
+        Vector getPositionAt(double dist) const;
 
     private:
         Vector  m_origin;