Hi, Apart from being a total waste of polygons (would be sorted for final release, obviously) - is there a known issue with intersecting boxes? e.g. two boxes, one inside the other partially? I ask because I created what I considered to be a low-poly count (1000 or so) model, no textures, no animations etc., and it was sooo slow!! From running at 45 FPS with the default Cessna to 12 FPS. Am I doing something wrong? I note also that cloning (mirroring) a part seems to have a performance hit, even though the part that was cloned added maybe 50 polys to the count. Anyone aware of any issues?? This is in FS2004. Best regards, Robin.