"pakled": I never use the "smooth polygons" option so it is always unchecked.

"markschum": What you are talking about is CAST shadows. What I'm talking about is the the shadowy part of the object itself. Like if you have a sphere and there's only one light source from the left hand side, then the right part of the sphere will be in darkness. Now in the middle of the sphere, where the transition from light to shade happens, the light and dark areas will be merged in a blur. I want a crisp line seperating the two areas.

Thank you both for your suggestions, but I'm starting to get the feeling that the effect that I am looking for cannot be achieved with Poser's rendering engine. So can anyone suggest a really good Rendering software which is compatible with Poser? i.e. I should be able to export Poser objects and import them into the Rendering Software.