The type of Sky an Ambient lighting to be used are specified in the Sky Settings dialog.
Sky types
Plain Color - Uses a plain solid color.
Graded - A gradual change is made from the horizon up to the zenith.
Environment map... - An image file stores the picture used as an environment map. An environment map can be imagined as a painting on a sphere far out into space surrounding all the Actors. The map is used four times in a complete revolution, and twice between horizon and zenith. In other words, if the camera was to rotate through 360 degrees it would see four copies of the environment map. Hint: Use an environment map that is seamless in both the up/down and left/right directions. The use of an environment map gives a very good sense of movement when the camera is flying around and looking at a model.
Backdrop image... - Use a image held in a picture file instead of a plain color background. If the image file is not of the same dimensions as the animation, it is appropriately scaled. Notes: By using more than one timeline in the Sky Actor costume, the sky can be made to change color during an animation. A dawn or sunset sequence can be simulated because the colors set in the keyframes may be different and the Renderer will tween color in the same way that it tweens other parameters.
Animated Backdrop... - Use a series of images (Map001.gif, Map002.gif, Map003.gif...) as an animated background. If a value of 1 is specified in the Step Box, then Map001.gif will be the background for Frame 1, Map002.gif will be the background for Frame 2, Map003.gif will be the background for Frame 3, etc. If a value of 2 is specified in the Step Box, then Map001.gif will be the background for Frame 1, Map003.gif will be the background for Frame 2, Map005.gif will be the background for Frame 3, etc.
View Button - Displays the specified Environment or Backdrop image.
Ambient lighting
Ambient light illuminates Actors from all directions at the same time. Therefore an image will appear brighter if there is a proportion of ambient light present. However, if the proportion is too high the image will have very little contrast and will appear washed out. A maximum value of 50% is acceptable.
It is possible to set the ambient lighting for the ground and the models separately. There are many possible lighting conditions where the ambient light applied to the ground should be quite high while the ambient lighting for the models is most appropriately kept low.