OpenGL only has problems in programs that aren't programmed to deal with it. My guess is mainly that since Bryce's booleans and whatnot aren't actual geometry, then OpenGL can't actually read them properly and THIS is the nature of it's lag and low detail. Same with the terrains : they aren't converted to polys until rendertime, technically. This follows along the lines of "exportability". I imagine that when they fix one, they'll fix both. Here's a screenshot of GL in Maya. This is realtime, and flows at about 50 FPS on my Geforce 4 MX 440, with 64 MB on-card RAM. This model won't even LOAD into Bryce, much less perform a GL preview...