It’s Time For a New Leader! (Learning Curve AutoCAD Tutorial)30 Apr, 2008 By: Bill Fane
Add or remove arrows, align and collect leaders, and more with these two leader commands.
It was a beautiful, crisp, clear spring day. It was the second day of spring — March 22 to be precise. Captain LearnCurve had spent the day skiing, and in the early evening he and his gorgeous wife were on their way to a ballet recital performed by their eight-year-old granddaughter Rebecca.
They parked the car and entered the local community hall.
Suddenly a shout rang out. More accurately, more than 80 shouts rang out.
It took a moment for the captain to realize that they were shouting at him, for it was his 65th birthday party. There was no ballet recital tonight. His wife had led him astray.
Hmmm, led, leader? that's it! This month's topic!
Your segues don't improve with age, do they?
In last month's Learning Curve, we saw how AutoCAD now has four different commands for creating leaders. The resulting leaders all appeared to be identical, but an analysis of the first two of them showed a number of internal differences.
This month we will move right along to investigate the third and fourth leader commands: the QLeader (Quick Leader) and the new MLeader (Multi Leader), which was introduced in AutoCAD 2008. By the way, the title of this article has nothing to do with politics.
Let's do the easy one first. Last month we studied the original Leader command that was found within the Dim subcommand prompt, and the newer Leader command that runs from the regular Command prompt. In particular, we saw how the later Leader command has a number of formatting options available so we can draw splined leaders, or insert a predefined block as a symbol instead of supplying text, or create a geometric dimensioning and tolerancing (GDT) symbol at the end of the leader. Each of these options is available as a Command line option.
The Qleader performs exactly like the Leader command, with all the same options, and produces the same type of leader object. The only difference is that the various formatting options are available through a dialog box instead of as Command line entries.
To see this box, start the QLeader command. In earlier releases it is available through menu and toolbar selections, but in AutoCAD 2008 and later, it can be accessed only through the Command line.
When it starts, it displays the following prompt:
Specify first leader point, or [Settings] <Settings>:If you select a point, it behaves like the Leader command, but if you just press Enter, it brings up the Leader Settings dialog box with three tabs. The options should be pretty obvious, and they mostly match the Format options of the Leader command.
The three tabs of the QLeader's Leader Settings dialog box control all of Qleader's options.
Okay, now that we have QLeader out of the way, let's take a look at the new (to AutoCAD 2008) MLeader command. It is available under the Dimension menu pick and in its own Multileader toolbar and on the Multileaders panel of the AutoCAD 2008 dashboard and on the Annotation panel of the Home tab of the AutoCAD 2009 ribbon menu.
Wait a minute! If MLeader is just a command, how come it rates its own toolbar and command panels?
There are two universal rules of life. Rule number 1: Never divulge everything you know at one time. Rule number 2: I'll tell you later.
When the MLeader command is started, it presents the following options:
Specify leader arrowhead location or [leader Landing first/Content first/Options] <Options>:If you simply pick a point for the leader arrowhead, it behaves exactly like the Leader or QLeader commands. It asks for a landing location, and then it brings up a request for text along with the MText editing toolbar.
On the other hand, let's look at the other choices.
Who's on First?
Start the Leader command again, but do not pick a starting point this time. Instead, enter the letter L at the Command prompt. This reverses the normal location selection process. It asks for the leader landing point first, then the location for the arrowhead point, and finally the text.
The Content first option asks for the location of the text, then the content of the text, and finally for the arrowhead point.
Interestingly, MLeader remembers the last sequence you used and offers it as the default the next time.
Even more interesting is the fact that specifying options at the initial prompt reverts to the Command prompt options of the old Leader command rather than using a dialog box like QLeader. I won't go into all of the details of the various options because there is much more interesting stuff to come.
It's Later Than You Think.
Earlier I said I would reveal the truth a little later. Well, it's later! Now we'll see why MLeader rates its own toolbar and command panels. The secret is that MLeader is not just a single command, but is actually a family of them.
The Multileader toolbar gives access to the multileader family of commands.
Working from left to right, the first button is the basic MLeader command.
The next two buttons start the MLeaderEdit command and invoke either of its two options. The + button lets you add additional leader arrows to an existing leader object, and the X button removes them.
The MLeaderEdit command is used to add or remove additional leader arrows to an existing MLeader object.
Okay, you have now placed a number of leaders in your drawing. Perhaps it is an assembly drawing, and you have added item number tags to the various parts. Initially, you placed them more or less at random, but now you want to tidy things up a bit.
M Is for Magic
Start the MLeaderAlign command. This is the fourth button from the left of the toolbar. Select several MLeader objects and press Enter. Next, pick a starting point for the alignment and then the second point. Like magic, all the leaders align themselves so that the end of the landing segment falls on the alignment line.
The MLeaderAlign command is used to neatly align mleaders.
The leader annotations normally space themselves evenly between the start and end points of the alignment specification, but available options allow you to specify an exact spacing or to make all the leader arrows parallel.
A significant point to note here is that AutoCAD's usual point selection modes such as polar, ortho, and object snaps are in operation during the alignment process.
Getting It All Together
A common situation in assembly drawings occurs when several components are arranged in a virtual subassembly. For example, a nut, two washers, a lock washer, and bolt all go together. For simplicity we just want a single leader that contains several different item numbers.
The fifth button handles this case. It invokes the MLeaderCollect command. Simply select the leaders to be collected and then specify a location point for the collected annotations.
The MLeaderCollect command collects multiple leader annotations into a single leader.
What, you tried that but it didn't work? Okay, maybe it isn't quite as simple as it might look. Actually it is; it just doesn't look that way.
For starters, it works only if the annotation objects are block insertions. Let's take a look at that topic and then come back to the collection issue.
I commented earlier that the options of the MLeader command seemed rather limited and Command prompt driven. That's not quite true. In fact, it isn't true by quite a bit.
Look at the far right-hand button of the Multileader toolbar. It invokes the MLeaderStyle command. That's right. MLeader options can be set and saved as different styles of mleader. If you need several different styles within a drawing, you no longer need to manually flip the options back and forth. Better still, named styles are saved within the drawing, so you can easily create a template file that has your styles predefined and ready to roll in any drawing that you create from the template.
The initial Multileader Style Manager dialog box looks very much like the Dimension Style Manager dialog box. It has a left-hand window that lists available styles, a center section that previews the current style, and a list of operation buttons. Let's start a new style based on the current standard style.
The Modify Multileader Style dialog box has three tabs. I won't worry about the first two, because the options they set are pretty obvious.
The one of interest to us at this time is the Content tab. It has a dropdown list from which you can choose Block, Mtext, or None.
Choose Block as the Multileader type. The dialog box tab changes to show block properties. The item of interest here is the Source Block dropdown menu.
The Edit Multileader Style dropdown contains six standard block definitions to use as mleader annotations.
Each of the six predefined blocks includes suitable attributes, so you can just fill in the blanks as you create each mleader. You can also use a block definition of your own creation.
Now the operation of the MLeaderCollect command becomes simple, with a couple of procedures and variations. The order in which you select the mleaders to collect is very significant. The symbols will be displayed in the order in which you select them, first to last, and the arrowhead of the last one selected is the one that survives and so defines the single leader arrow. If a Window or Crossing selection method is used, the order is based on the creation sequence, with the youngest being first and the oldest being the last.
The MLeaderCollect command can collect multiple leader annotations into a single symbol.
Once you have finished selecting the mleaders you want to collect, you still have three options. You can have the symbols arranged horizontally, vertically, or wrapped.
The last one is an interesting option and is used when you are collecting a large number of leaders. If you enter a distance, AutoCAD wraps the symbols into multiple rows so that the total width does not exceed the specified distance. On the other hand, you can also specify a specific number of symbols per row.
By the way, mleaders can also be annotative, so that their sizes and proportions adjust automatically to suit the drawing scale. MLeaders are indeed a powerful weapon in our documentation arsenal.
No AutoCAD users were harmed in the testing of this article.
And Now For Something Completely Different...
If my wife invites you to a ballet recital, it may turn out that you are not actually going to a ballet recital.
About the Author: Bill Fane
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