If you’ve drawn splines in previous versions of AutoCAD, you might notice something missing in AutoCAD 2011. The drawing process has been streamlined by eliminating the need for you to specify the starting and ending tangencies. Instead, AutoCAD assumes tangent directions based on the points you pick. If you want to change tangency of a Fit spline, you can manipulate it directly on the spline by hovering the cursor over the starting or ending grips and choosing Tangent Direction from the menu.
In addition to direct manipulation, you can modify the tangent directions using the Properties palette by entering values for the X-, Y-, and Z- tangent vectors.