Black holes in the screen

i made an application and it all works finde. but if a rotate the node or the cam, there are black holes emerging. the boxes and quads are only drawn partially. why this? anybody knows?


Are the boxes/quads far away from the camera? Most likely they're behind the camera's far plane, so they are "out of sight" of the camera.

i dont think they are out of sight, because i dont zoom out, just rotate. but i could increase the far plane and check if the errors are still there