Check the video, bush disappears when display LOD4. **(b_corylusHeterophylla_2s_summer.p3d)**
{F3018283} https://youtu.be/VzJwbuZ8Zec
!!There is a case in LOD4 (angle of 60°) when all faces of boxes facing by normal to oposite direction of camera.!!
!!When you flip the marked box, this situation will never occur again.!!
{F3019759} Blue faces facing with normals to the camera and red away from the camera.