HI IO4,

It's only in Bryce v6.1 - do you have this version? Like dan said, its not well documented and though its mentioned as a new feature in the pdf version of the 6.1 Help File, it doesn't actually say where the feature is! I'm not in front of Bryce at the moment, but here goes...

No, its not optimisation, but you'll find it under the 'Render Options' menu (the lowest little triangle on the left hand side of the main Bryce Window - near the trackball?) Anyway, when you click on that, it brings up a menu - there is a menu item called Priority (its either the 2nd or 3rd item in the list). Select Priority and then you'll see three options - Low, Medium (the default) and High. Set it on High, and then you're renders will complete mcuh faster! Open up the Task Manager in Windows to see the difference - on the Medium setting, Bryce only ever utilises a maximum of about 50% of the CPU - select the High priority setting in Bryce though, and it'll utilise 100% of the CPU! Thats more like it! :-)