Posted By Mike Williams on January 31, 2009

If you’ve used AutoCAD for any length of time, there’s no doubt you’ve found the OFFSET command by now.  If you’ve found the OFFSET command, surely it is one of your favorite commands.  The OFFSET command is a perfect example of something I’ve seen time and time again.  It could almost be a metaphor of most of our AutoCAD knowledge.  Let me know if this describes you to any extent.  Here we go…

You learn how to do something new in AutoCAD.  Maybe it’s a new command, technique or short cut.  You’re excited and immediately start using it.  In this case the OFFSET command.  You realize how it differs from the copy command and start offsetting objects left and right.  Then you place it in your box of tools and move on.

But so often, we never learn the full extent of the command and all of its options. For years, I would offset an object, and then erase the original.  When needing to offset several times, I would keep picking the last object that I just created and offset it again.  Or how many times have you offset an object, only to select it and change its layer?

If you’ve been guilty of any of the above scenarios, get ready to expand your mind.  There are several options to the OFFSET command that greatly improve its power and usefulness.

When you execute the OFFSET command  you are prompted as follows:

Specify offset distance or [Through/Erase/Layer] <Through>:

What you may not have noticed is the text in the command line above it:

Current settings: Erase source=No Layer=Source  OFFSETGAPTYPE=0

As a matter of fact, you may not read anything from the command line and just enter the offset distance or pick it on the screen.  Let’s take a look at each option to unlock the full potential.

But first, a Bonus tip on reading the command prompt.  At the end of the prompt is <Through>.  Whatever is written between the < > is the default action (the action that will be taken if you give no other options or press the Enter key.)  Whatever letter/s is capitalized in the list of options is the shortcut letter for executing the option.  In this case, “T” = Through, “E”= Erase and “L” = layer (you do not have to capitalize the letter to select the option).  That’s why some commands have other letters capitalized rather than the 1^st and sometimes has multiple capital letters.

Ok, back to the offset command.  When you execute the command, without selecting any options, you can simply pick the point to measure the distance (or type a distance) and then it prompts you to pick the object to offset.  If you enter the option “t”, it will ask you to select an object first and then ask you to “specify through point”, which means, pick another point so it can calculate the distance.

If you enter “e” after executing the OFFSET command, you get a prompt saying:

Erase source object after offsetting? [Yes/No] <No>

The default is the current setting (”No” if you’ve never toggled it before), but if you type “Y”, you are returned to the prompt to enter or select the distance and the object. Whatever object you pick, it (the source) will be erased and you will be left with only the newly offset object. It’s important to note that this “erase mode” will remain in effect until you change it.

If you enter “L” after executing the OFFSET command, you will get a prompt saying:

Enter layer option for offset objects [Current / Source] <Source>:

The default is the current setting (”Sources” if you’ve never toggled it before) which means the new object will be on the same layer as the source object.  If you toggle it to “Current”, all offset objects will change to the current layer (so make sure you set the desired layer first).

The last item in the command line above the OFFSET prompt is the current setting for the OFFSETGAPTYPE system variable.  This variable has 3 settings to control what happens to the potential gaps between segments when you offset closed Polylines.   The settings are as follows:

0  -  Gaps are filled by extending the polyline segments.

1  -  Fills the gaps with filleted arc segments with a radius equal to the offset distance.

2  – Fills the gaps with chamfered line segments with perpendicular distance to each chamfer equal to the offset distance.

What???  A picture is worth a thousand words (or at least 47 words in this case).  So this should help:

There, much better, don’t you think.

After picking the object to offset, the prompt changes to this:

Specify point on side to offset or [Exit/Multiple/Undo] <Exit>:

The default is to “Exit” the OFFSET command if you press Enter.  If you pick a point, it will offset the selected object and if you type “U” for “undo”, the previous object that you offset will be undone.  Picking “undo” in the offset command will only undo the last offset object, but picking “Undo” after the OFFSET command is finished and you are back at the “Command: ” prompt will result in undoing ALL the offsets you performed during your last OFFSET operation.

The final option is “M” for “Multiple”.  This option rocks!  And for some reason, I didn’t use it (or know about it) for years.  That will teach me to read the command line. If you select the “Multiple” option, you can repeatedly pick the side to offset onto and AutoCAD will use the same distance and other settings previously set.  Then you can do some rapid-fire offsetting. Pretty awesome.

I hope you learned something new about the OFFSET command.  Don’t forget to post a comment below.

Thanks for Subscribing,

Mike

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Categories: tips
Tags: offset, offset multiple, offsetgaptype, tips