SPLINE allows you to alter the shape of an existing 
spline, without completely respecifying all node points
and end conditions.

Select the spline to be modified, and choose one of the
following options:


MOV NOD (move node) - you to move existing node points on 
a spline. Temporary for easier manipulation, markers (x) 
are automatically displayed at each existing node point of
the spline. 

CHG END (change endpoint) - to modify the end condition of
an existing spline for any of the following purposes:

NATURAL - to assign a curvature of zero to the appropriate
end of the spline.

2 PTS - to specify a tangent vector at a spline endpoint
by indicating two points.

ENDENT - to specify a tangent vector by using the tangency
at the end of an existing entity.

TANGENT - to enter the x, y, (and z if 3-D) vector
components and magnitude of a desired tangent vector.

ANGLE - to specify a tangent vector at a spline endpoint 
by entering an angle in degrees. This option is for 2-D 
splines only.

2-D/3-D - to automatically convert a 2-D spline to 3-D 
form so that a spline is no longer forced to lie within a
particular plane when edited. Changes are represented only
in the database, which allows you to move nodes, if
necessary. The amount of space in the database
automatically increases to store the spline.
