GLOSSARY
Aspect ratio describes the proportions of a still image or the frames in a movie, expressed as the ratio of width to height. For example, pre-1950s movies and 35 mm slides have an aspect ratio of 4:3.
Aspect ratio is usually expressed either as a ratio of width over height (for example, 4:3) or as a real value relative to 1 (for example, 1.333).
When you make a spotlight a projector, set the spotlight’s aspect ratio to match the aspect ratio of the image it’s projecting (with the Bitmap Fit button). If you don’t, 3DS MAX stretches (and distorts) the bitmap to fill the projector cone.
3DS MAX also allows you to set the pixel aspect ratio, so that there is a different value for the distance covered by one pixel measured horizontally and one pixel measured vertically.