OBP's are a native Bryce file format and only work in Bryce. However, about 80 per cent of OBP's can be exported from Bryce (using the Bryce Export Easter Egg) as long as they are not Booleans. You will instantly know during the first phase of the export if it will export or not. Bryce guru's Wolfiesden.com and Fastraxx have both created tutorials on this. Check your local listings...