0 to 1. Values less than 0 are adjusted up to 0. Values greater than 1 are ad-justed down to 1. No messages are given when adjusting.
Set it to 0.5 for production-level anti-aliasing, especially when working with sub-tle differences in shading. Set it to 1 if the picture shows high contrast. When set to a high threshold, less anti-aliasing is performed, resulting in quicker ren-dering. A set-ting of 0 forces maximum pixel subdivision everywhere.