Generates a 3Dview, given a view position and a view direction.
viewvector A three-element vector containing the direction to look.
perspective The perspective projection distance. The smaller the projection distance, the more "severe" the projection is. The larger the projection distance, the more "isometric" the projection is.
TIP: To prevent a perspective projection, set perspective to 0 (or less than zero).
viewup A two-element vector containing the final 2D view up vector. For a "right-side-up" view, set this parameter to [0.0, 1.0].
viewcenter A two-element vector containing the window location on which to place the viewpoint. It is in normal coordinates and is usually set to [0.5, 0.5].
winx, winy The x and y dimensions, respectively, of the plot window in device coordinates. Typically, winx and winy are set to the X and Y size of the current graphics window.
xr, yr, zr Two-element vectors containing the minimum and maximum x, y, and z values, respectively, found in the data to be plotted. The minimum value is in xr(0), yr(0), and zr(0); the maximum value in xr(1), yr(1), and zr(1).
SET_VIEW3D changes the system viewing matrix !P.T, as well as the system variables, !X.S, !Y.S, and !Z.S, which handle conversion from data coordinates to normal coordinates. (These system variables are described in Chapter 4, System Variables.)