Matty's Rocket requires a great deal of 3d modeling and painting work to produce backgrounds for the animation. My initial work begins from working on the storyboards. At that stage I either collect photographs for elements (sky, clouds, etc.) or go straight to modeling in a 3d modeling application (3ds max). In 3ds max I attempt to light the scene then output a high resolution tiff render with alpha channel. From their I do a paintover in Photoshop broken down into layers. This allows the background to be ready for compositing.