A model whose box is wholly outside what a camera sees is skipped before it costs anything: its numbers, its draw, every corner the card would have moved. So a field of 625 cubes costs what is in front of you. Each camera decides on its own, so what one leaves out another still draws. There are no shadows here, but a shadow is judged by its light in the same way, so a model out of the picture still throws one into it.
From the camera itself you cannot see it happen: what it skips is exactly what it would not have shown. So the picture in the corner looks from above, and is told to draw only what the eye sees: above.cullingCamera = eye. The yellow lines are the eye's view. Walk with the arrows and the field appears ahead and vanishes behind; C lets the camera above draw everything again.
A model that bends is judged in the pose it is in. One whose material moves its corners in a vertex hook is always drawn until it says how far they go, boundsMargin: 0.4, in its own units; alwaysDrawn: true never skips one.