Tutorial Solutions
Illumination

1. The Phong illumination model refers to the use of a local illumination model having a specular term
   

     (R.V)^N
   

   The Phong shading model is often used to refer to a scan-conversion of the components of the surface normal so that they can be used in a local illumination model, such as the Phong model.
   
   
2. The specular component will be a maximum at the bottom (R.V=1) and zero after the point where R.V=0, because for the top of the polygon, R.V<0

   The diffuse component is independent of the viewing angle, so is strongest at the point closest to the light source, and tapers off towards the edges. See your tutorial discussion for details.