I’m going through the Blender Underground #5 video on materials and I’ve seen this problem before. Essentially, the polygons facing away from the light source don’t render at all, and I end up with hard, jig jag renders as you see in the attached. Anyone know what this is about?
This is easily repeatable. I start a new scene, replace the cube with a UV Sphere and set the hardness to 1 on the default material shader I see this sort of thing when rendered.
Blender 2.49a (desktop) and 2.48a (laptop).