Read the Bryce Forum FAQ link at the top of the page above the banner box. The 3rd FAQ down tells what you can import The fourth FAQ tells how to export and what keystrokes to hit. You can not export the basic bryce shapes you see on the top of the bryce desktop. You can't export any of the Bryce objects from the first create menu. If you create an object by boleans like using an imported cube to cut a window into another imported cube then export you wind up with two cubes. Bryce won't export the hole.