The Background button displays the Sky Color, Ground Color, and Images rollouts. Use these rollouts to specify colors and images for the sky and ground in your VRML 2.0 world.
The Sky Colors rollout lets you provide a colored background to the world’s sky using a gradient of up to three colors. The sky is an infinite sphere that encloses the objects of the scene.
The Ground Colors rollout lets you provide a colored background to the world’s ground plane using a gradient of up to three colors. The ground appears inside the sky sphere and below the objects of the scene.
The Images rollout lets you specify a set of images that define a background panorama between the ground/sky backdrop and the objects in the scene. The panorama consists of six images, each of which is mapped onto a face of an infinitely large cube centered in the local coordinate system.