Modifies the properties of a spline; converses a spline to a polyline.
Note: It is easier to edit the spline and its grips when Snap is turned off.
Accessing the Command
command bar: splinedit
transparent: 'splinedit
menu bar: Menu command
toolbar: Modify 
: SplinEdit
Prompts you in the command bar:
Select spline: (Select a spline entity)
Edit spline [Close/Join/Fit data/Edit vertex/convert to Polyline/Reverse/Undo/eXit] <eXit>: (Select an option)
Edit spline [Close/Join/Fit data/Edit vertex/convert to Polyline/Reverse/Undo/eXit] <eXit>: (Select another option, or else press Enter to end the command)
Command Options
Option 
Description 
Select spline to edit 
Selects the spline to which the editing operations should apply: pick a single spline. The program shows the spline's fit points (green squares) and places a triangle at the start of the spline: 
Close or Open 
Depending on whether the selected spline is open or closed, one of the options is available:

Join 
Joins the spline with an open 2D entity that shares an endpoint with the spline (coincident endpoints); you can join lines, polylines, arcs, elliptical arcs, and other splines. Prompts you:
The entities joined to the spline take on the properties of the spline, such as its color and linetype. 
Fit Data 
Edits fit point data using several options; fit points determine the curvature of the spline. Prompts you: Edit fit data [Add/Close/Delete/Kink/Move/Purge/Tangents/toLerance/eXit] <eXit>  (choose an option:) Add  adds fit point between two existing ones; prompts you:
Close/Open  closes an open spline by connecting the start and end points, or else opens a closed spline by removing the segment between the first and last points when the spline was originally created. Delete : Removes fit points; prompts you:
Kink  adds a knot and fit point at the specified location on the spline, which does not maintain tangent or curvature continuity at that point; prompts you:
Move  moves a fit point; prompts you: Enter new location or [Next/Previous/Select point/eXit] <N>  (the program automatically selects the first fit point, the one marked by the triangle; enter an option:)
Purge  replaces the fit data from the spline with control vertices: Tangents  changes the starting and ending tangents of an open spline; prompts you:
For closed splines you are prompted to define the tangent at the point of closure. Tolerance  refits the selected spline to the existing fit points using a new tolerance value; prompts you: Enter fit tolerance <0.000000>  (type a value.) Exit  accepts the changes and returns to the previous prompt. 
Edit Vertex 
Edits control frame date using several options; prompts you: Edit vertex [Add/Delete/Elevate order/Move/Weight/eXit] <eXit>  (choose an option.) Add  adds a new control vertex at the point you specify; prompts you:
Delete  removes control vertex; prompts you:
Elevate Order  increases the polynomial order (degree plus one) of the spline to increase the number of control vertices across the spline; the maximum value is 26. Prompts you: Enter new order <xx>  (type an integer.) Move  relocates control vertices one by one; prompts you:
Weight  changes the weight of a specified control vertex and then recalculates the spline based on the new weight value; larger weights pull the spline closer to the control vertex. In the figure below, the red control vertex has a weight of 1: And here the red control vertex has a weight of 6: Prompts you:
Exit  accepts the changes and returns to the previous prompt. 
Convert to Polyline 
Converts the spline to a polyline. The precision determines how closely the resulting polyline matches the spline: values between 0 and 99 are accepted, with higher values creating more polyline segments. Prompts you: Specify a precision <10>  (enter an integer.) The PLINECONVERTMODE variable specifies the kind of polyline to convert to:

Reverse 
Reverses the direction of the spline; the triangle icon appears on what was formerly the spline's end point. 
Undo 
Undoes the previous modification. 
Exit 
Concludes the editing of the spline. 
Related Commands
Join  joins lines, LW polylines, 2D polylines, 3D polylines, circular arcs, elliptical arcs, splines and helixes at their common endpoints.
PEdit  edits polylines, 3D polylines, and 3D meshes.
Spline  draws open and closed splines.