by negke » Sun Feb 12, 2012 8:43 am
The lightmaps are stored in the .bsp. No engine can smoothen them or make them look better.
The light tool, at least a modern version like Bengt Jardrup's, has several additional options for better shadowcasting. Generally, for a final compile you should use -extra4, and there's also a -soft parameter for even smoother rendering.