Background Settings Dialog
The Background Settings dialog lets you select an image to display behind your model in 3D view when the display mode is set to Rendered or Rendered Outline, or when you are creating a 3DTrueView™ rendering.
Day Scene. Select this radio button to create a daytime scene.
Night Scene. Select this radio button if you are creating a night-time 3DTrueView rendering.
Click the preview to select an image from the Materials dialog.