AutoCAD Modifying spline curves

For a spline curve object created with the "spline" command, the user can modify it using the "splinedit" command. The command is invoked in the following way:

Toolbar: "Modify II (Modified II)" →

Menu: "Modify (modified)" → "Object" → "Spline (spline curve)"

Shortcut menu: Select the spline curve you want to edit and right-click and select Spline edit (Edit spline curve)

Command line: Splinedit (or alias SPE)

After the command is invoked, the system prompts the user to select the spline curve, and gives you a variety of action options:

Select Spline:

Enter option [Fit Data/close/move Vertex/refine/reverse/undo]:

The specific roles are as follows:

(1) "Fit data": The fitting data consists of all fitting points, fitting tolerances, and tangent lines associated with the spline curve. When the user selects the item to edit the fitted data, the system prompts you to select the following fitting data option:

Enter A Fit data option

[Add/close/delete/move/purge/tangents/tolerance/exit] <exit>:

The effects of the above options are shown in table 7-5.

Table 7-5 use of the Fit data option

Options	Role
Add (added)	Add the fitting point in the spline curve. AutoCAD will then fit the spline curve with the newly set point.
Close (closed)	Closes the open spline curve and causes its tangent to be contiguous at the endpoint, and for closed spline curves, the item is replaced by Open.
Delete (delete)	Deletes the specified fitting point from the spline curve and then uses the remaining points to fit the spline curve again.
Move (moving):	Move the fitting point to the new location.
Purge (Cleaning)	Deletes the fitted data of the fitted curve.
Tangents (tangential)	Edit the start and end tangent of the spline curve.
Tolerance (tolerances)	Modifies the tolerance of the current spline curve, and the system will redefine the spline curve according to the new tolerance.
Exit (Exit)	Exit the Fit data option to return to the main option.

(2) Close (closed): Closes the open spline curve so that it is tangent continuous at the end point. If the starting point of the spline curve is the same as the endpoint, the close option causes it to be tangent continuous at two points. For closed spline curves, the item is replaced by Open, which works the opposite way.

(3) "Move vertex (moving vertex)": Reposition the control vertex of the spline curve and clean the fitting point.

(4) "Refine (precision)": Precision adjustment spline curve definition. When the user selects the item, the system prompts you to select the following fitting data option:

Enter a refine option [Add control point/elevate Order/weight/exit] <exit>:

The effects of the above options are shown in table 7-6.

Table 7-6 The use of the "Refine" option

Options	Role
ADD Control Point (Add control Point)	The specified control point is increased from one to two when the spline curve is kept in the same precision.
Elevate Order (Ascending order)	Increase the order of the spline curve. The higher the order, the more control points of the whole spline curve, the more strict the control. The maximum number of orders is 26.
Weight (weight value)	Modify the weight of the control point. The larger the weight, the closer the spline curve is to the control point.
Exit (Exit)	Exit the Refine option and return to the main option.

(5) "REverse (reverse)": reverse the direction of the spline curve. This option is used primarily by applications.

(6) "Undo (Discard)": Cancels the last edit operation without exiting the command.

Note the spline curve will lose the fitted data if you do the following.

? Use the Purge option when editing the fitting data.

? Redefine the spline curve.

? The spline curve is fitted by tolerance and its control vertex is moved.

? Fit the spline curve by tolerance and turn it on or off.

You can also use the "splinedit" command for spline multiple segments to modify the system to convert the spline multiple lines into spline curve objects, but the converted spline curve objects do not fit the data.