AutoCAD Modify multi-segment line

For multiple-segment line objects created with the "pline" command, users can modify them using the "pedit" command. The command is invoked in the following way:

Toolbar: "Modify II (Modified II)" →

Menu: "Modify (modified)" → "Object (object)" → "Polyline (multi-segment line)"

Shortcut menu: Select the multi-line line you want to edit and right-click, and select Polyline Edit (Edit multi-segment line)

Command line: Pedit (or alias PE)

When this command is invoked, the system prompts the user to select a multi-line line first:

Pedit Select polyline or [multiple]:

Users can select multiple segment line objects by selecting the multiple option, otherwise only one multi-line object can be selected. If the user selects a line, Arc (ARC) object, the user is prompted whether to convert it to a multiple-segment line object:

Do your want to turn it into one? <Y>

When the user selects a multiple-segment line object (or converts a line, arc, and other objects to a multi-line object), the system further prompts:

Enter an option [Close/join/width/edit Vertex/fit/spline/decurve/ltype Gen/undo]:

The specific roles are as follows:

(1) "Close": a closed, open, multiple-segment line. Note that even if the start and end points of a multi-line line are at the same point, AutoCAD still considers it open and must use this option to close it. For closed multi-line lines, the entry is replaced by Open, which works the opposite way.

(2) Join (merge): Merges a line, arc, or multi-segment line object with other segments of the line that coincide with its endpoint to form a multiple-segment line. For curves fitting multiple segments, the curve fitting is removed after merging.

(3) "width": Specifies the width of a multiple-segment line, which is valid for each segment of a multi-line line.

(4) "Edit vertex": used to edit each vertex that makes up a multiple-segment line. When the user selects the item, the first vertex of the multi-line line is labeled "X", and if the vertex has a tangent, the arrow is also plotted in the tangent direction. The system further prompts for the following selection:

Enter a vertex editing option

[Next/previous/break/insert/move/regen/straighten/tangent/width/exit] <n>:

The effects of the above options are shown in table 7-4.

Table 7-4 The use of the "Edit vertex" option

Options	Role
Next (Next)	Move the tag "x" to the next vertex
Previous (Previous)	Move the tag "x" to the previous vertex
Break (interrupted)	Saves the vertex position of the current tag "x" and prompts the user to select a different vertex, and then selects the "Go" option to remove the portion between the two specified vertices
Insert (INSERT)	Adds a new vertex after the vertex that marks "x"
Move (moving)	Modify the position of the vertex of the tag "x"
Straighten (straighten)	The operation is the same as the break option, but the result is to replace the portion of the two specified vertices with a straight line segment instead of deleting
Tangent (tangential)	Modifies the tangent direction of the vertex of the marked "X", which is used for subsequent curve fitting.
Width (breadth)	Modifies the start and end widths of line segments behind the vertices of the mark "X"
Exit (Exit)	Exit the "Edit vertex" option and return to the main option.

(5) "fit": two vertices are added between each two adjacent vertices to produce a smooth curve, which consists of arc segments connecting each pair of vertices. The curve passes through all the vertices of the multi-line line and uses the specified tangent direction.

If the original multi-segment line contains an arc segment, it is equivalent to a straight segment when generating a spline curve. If the original multi-line line has a width, the resulting spline curve transitions from the width of the first vertex to the width of the last vertex, and all the middle width information is ignored.

(6) "Spline (Spline curve)": Using the vertices of a multi-line line as a control point to generate a spline curve that passes through the first and last control points, but not necessarily through other control points. This kind of curve is called B-spline curve. AutoCAD can be generated two or three times spline fitting multiple segment lines.

(7) "Decurve (non-curved)": Removes the redundant vertices inserted by the fitting curve and spline curve and restores all segments of the multi-line line to a straight line, but retains the tangent information that is assigned to the vertices of the multiple segments of the line. However, it is not "not curved" to fit multiple segments of a spline that is edited by using the command "break", "trim", and so on.

(8) "Ltype gen": If the item is set to "on", the multi-line object is generated as a whole, and if set to off, the line style is generated at each vertex at the beginning and end of the dot dash. Note that this item does not apply to multiple segments of a line with a widening segment.

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

The "Pedit" command can also be used to modify three-dimensional multi-line and three-dimensional grids, as regards the three-dimensional multi-segment and three-dimensional grids, see chapters 19th and 20th.