objects invisible in camera view

hi all,

I am just about to finish a simple lego brick. but I have some questions:

  1. how can I create a solid cylinder, like a tyre or a disc with a certain thickness? I tried to extrude a plane I made to a circle but I got two circular planes parallel to each other.
  2. I tried to look at it from the camera point of view. but I don’t see anything but a dashed square :frowning: I have set the camera to track the brick and in the 3d window I can see it moving with the object also and all layers are selected. But somehow the camera view doesnt show anything. Anybody know what could be wrong?