AutoCAD Lengthen Command

The LENGTHEN command has been around for over 18 years, it was introduced with Release 13 in November of 1994. Yet, I still see many instances where it is ignored and some other method is used in its place. So what can you do with the LENGTHEN command? Let's look at the 4 options, or ways it can work.

  • DElta - Use this option to extend or trim a Line or Arc when you want to add or subtract a certain amount. Let's say you have a line of unknown length but you want it to be 10 units longer. Use the DElta option and provide a value of 10, and the entity will be extended by this amount. Provide a value of -10, and the entity will be shortened (or trimmed) by this amount. You do not need to know anything about the original length and you do not have to draw (and later erase) any construction lines.
  • Percent - Use this option to extend or trim a Line or Arc by a certain percentage. Again, let's say you have a Line of unknown length and you want to double its length. Use the Percent option and provide a value of 200. If you want to trim the line in half, enter a value of 50. Using a value of 100 will do nothing since you are telling the command to make the line 100% of its current length... get it?
  • Total - Use this option when you want to make a line or arc a certain length, period. Take any line or arc, it doesn't matter if the Line or Arc you pick is 0.0001 unit long or 999999 units long, enter a value of 100 and the entity will be extended or shortened to be exactly 100 units long. This is an easy one to figure out.
  • DYnamic - Use this option when you don't know the original length and don't care what the resulting length will be. It allows you to graphically set the length using the cursor. To do it, pick near the end of a Line or Arc and simply drag the cursor to lengthen or shorten the entity.  There is a short video at the bottom of this post illustrating the DYnamic option.

All of the LENGTHEN options work off of the endpoint closest to where you pick. These are also easy commands to put in a menu macro or a shortcut lisp function. For example LD could be your shortcut for LENGTHEN DYnamic. Are you just starting out or are you an old AutoCAD veteran? Are you using the LENGTHEN command or other tools to do these things? Leave a comment and let us know. Thanks.

 

Comments

Worth mentioning is the effect the command has depending on which end of the object is selected. Dynamic obviously changes the object length from the end nearest the pick point. But in the case of Total the revised measurement will originate at the end furthest from the pick. This may not be obvious if the selection is made near the middle... so, always pick an end. :)

Hi! I use the lengthen dynamic all the time, but having to type in len and then dy. How do you create the shortcut as you mentioned in your post? I would love to be able to type in LD and be on my way!

You could use a lisp routine like this

(defun c:LD () (command "._lengthen" "_dy"))

Perfect, thank you!

 


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