How to use EXTEND command

Here is a free course how to use EXTEND command in AutoCAD

You can make objects longer using Extend and this command is similar to Trim because there are two steps to using it.

  • first you select 2D boundary objects (e.g. LINEs, ARCs, CIRCLEs, ELLIPSEs, POLYLINEs. TEXT & 2D SPLINEs).
  • then select 2D objects to extend to the specified boundary.

Command: EXTEND

Current settings: Projection=UCS Edge=None Select boundary edges …
Select objects: (pick LINE)
Select objects: ↵

Select object to extend or [Project/Edge/Undo]: (pick ARC)
Select object to extend or [Project/Edge/Undo]: ↵

  • There are other similarities between Trim & Extend
  • if you press <enter> instead of selecting boundary objects 
AutoCAD uses all objects (without highlighting them).
  • you can select any number of boundary objects and you select 
objects to extend one-at-a-time (unless you use a Fence).
  • where you select objects to extend is important (select object 
nearest the end that you want to extend).
  • the Edge setting is controlled by (the same) EDGEMODE system 
variable so boundary objects can imply extended boundaries.
  • The Lengthen command also lets you make objects longer (or 
shorter) without having to use boundary objects.


  1. Close the drawing from the previous exercise if it is open.
  2. Open the T108_3.dwg drawing file in your personal folder.
  3. Pick Modify + Extend. Select the horizontal LINE near P1 when prompted for boundary objects and press <enter> to signal AutoCAD that you have selected all boundary objects. Then pick the end of the ARC near P2 when prompted for objects to extend (do not exit this command yet).
See also  How to use Inquiry Tools For Points

  1. Right-click in the drawing area to invoke a shortcut and select Undo. (Remain in the same Extend command.)

  1. Pick the two ARCs near P1 & P2 to extend these ends of the ARCs to the boundary object and press <enter> to signal AutoCAD that you have selected all objects to extend.

  1. Trim the LINE used as the boundary in the last Extend command so your drawing looks like the illustration below.

  1. Save your changes to this drawing and Close the file.
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