BoxRatios
BoxRatios is an option for Graphics3D and SurfaceGraphics which gives the ratios of side lengths for the bounding box of the three-dimensional picture.
BoxRatios -> , , gives the side-length ratios. See The Mathematica Book: Section 2.9.10.
Further Examples
BoxRatios is an option for Graphics3D and SurfaceGraphics which gives the ratios of side lengths for the bounding box of the three-dimensional picture. 
, 
, 
gives the side-length ratios. 
