Using a computer program, rendering or image synthesis generates a photorealistic or non-photorealistic image from a 2D or 3D model. The resulting image is referred to as the render. Multiple models can be defined in a scene file containing objects in a strictly limited language or data structure. The scene file contains geometry, viewpoint, texture, lighting, and shading information describing the virtual scene. The data collected in the scene file is then passed to a rendering program to be processed and output to a digital image or raster graphics image file. The term "rendering" is analogous to the concept of an artist's impression of a scene. The term "rendering" is also used to describe the process of calculating effects in a video editing program to produce the final video output.