Aspect ratio is usually expressed either as a ratio of bitmap width over bitmap height (for example, 4:3) or as a real value relative to 1 (for example, 1.333).

Methods are available in the BitmapInfo class to get and set the aspect ratio property of the BitmapInfo(BitmapInfo::Aspect() and SetAspect()). Methods are available from the Bitmap and BitmapStorage classes to return the value of the BitmapInfo instance associated with the Bitmap or BitmapStorage.

3ds Max also allows users 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. A developer can check the pixel aspect ratio setting that is being used by the renderer using the method Interface::GetRendAspect().