If I wanted to add caves to my terrain, or dump huge castles on it, what would be the best algorithm/data structure to use for displaying there structures ? BSP ? Portal ? Nitzan ------------------------- www.geocities.com/nitzanw www.scorchedearth3d.net -------------------------

Well, I don''t know about the best , but a combination of Quadtree based terrain and portal based indoor enviroments sounds reasonable. Or you could use octrees for everything I suppose.

But the good thing about portals is that it''s not too hard to combine them with other methods - for each portal, you can store a flag specifying how the thing on the other side should be rendered - so that you look through a window, and the indoors is rendered with a portal based engine, and then the window portal has a quadtree on the other side.

John B