With Anti-Aliasing Bryce raytraces the scene to the pixel level then runs a 2D process on the resultant image which blurs sharp color transitions (kinda like Photoshop's Unsharp Mask). This is a way to speed up the rendering process but it also can blur detail and fine lines out of existence. Superfine is a different form of ray tracing called Distributed Ray Tracing. Since the scene has more internal data then screen/pixel resolution, DRT ray traces a block of data around the pixel and does a type of averaging to come up with the final pixel value. Since it's entirely 3D scene data (no 2D AA), it retains detail and fine lines much more accurately but at the cost of a slower render. It also improves the rendering of distant objects. HTH; Dan