If any of you have read that article about dynamic LOD''s then this might sound familiar: I''m implementing a ROAM engine that loads square maps, makes them into loadsa triangles, but only renders detail near to the camera (obviously). At the moment, when it renders, it only seems to tessellate the triangles to the lowest level of detail, wherever the camera is. I found out that this problem is because the difference between the height of a tri and the interpreted height (AKA variance) seems to be zero whilst rendering, even though it seems fine during init. I can''t think of anything that might zero it. Can anyone tell me the best way to either fix the problem, or rewrite the variance computing code please? If anyone''s made a ROAM engine w/ src code, then that''ll help as well... Thx. ======== Smidge www.smidge-tech.co.uk ========