This is a guest post by Edwin Prakoso (http://cad-notes.com/) @cad_notes on Twitter.
If you work intensively in AutoCAD 3D modeling, you probably already familiar with sub object. You can modify objects quickly and easily using vertexes. Gizmo in AutoCAD is very helpful. It is very easy to create 3D models in AutoCAD now. But have you used sub objects in 2D drawing?
If you are not familiar with sub object, we can use vertices, edges, faces, and solid history. If we work in 2D, we can only use vertices and edges.
But there are still many things we can do with it. Especially in AutoCAD 2011, Autodesk has implemented some nice enhancement here.
Selecting Sub Object
First thing first: how can we select subobject? For vertex, it is very straight forward. Select your object, then you can see the vertices in that object. Click the vertex to select it. We can only select a vertex at a time.
To select edges, you need to hold [ctrl] then click which edge you want to select. You can select more than one edges at a time.
Using Sub Object Selection Filter
If you are working on many subobject selections, then you probably want to use subobject selection filter. You can activate this filter and quickly select multiple edges without holding [ctrl]. You can find it in contextual menu: right click your mouse, and choose which subobject you want to filter.
Working with Vertex
Let us start with vertex. Vertex has many options we can use for modifying objects. Who knows, you probably will like it.
Stretching Vertex
The most obvious usage of vertex is to stretch it. You can lengthen a line; you can change a circle radius, etc. It’s very simple.
Now let us see the input options we can use when we select a line.
1. The default field that will be active is the extension length. If you type 5 then [enter], your line will be lengthen by 5 units.
2. If you press [tab], then your active field will move to another field. If this one is active, you can define the total length here.
3. You can also define the rotation angle, relative to previous angle.
4. And sure, you can define the angle from 0 degree of your current UCS.
Quite nice isn’t it? But remember, you need to have dynamic input active to use it. Probably there are not only 4 reasons to love dynamic input!
Using the Vertex Context Menu
This trick exists more than a decade. I remember I first use it in AutoCAD R.14. After you select the base point, then try to right click.
Let’s focus on the (1) part now. You can modify your objects, and use the vertex as base point right away. You can move, rotate, scale, or mirror your objects right away.
Now let us see the (2) part. These tools will move/copy the vertex (but not the whole object). You can define the base point, or you can simply copy the vertex. You can use it to offset a circle quickly with different offset distance.
Working with Vertex: Enhancements in 2011
Now if you are already using AutoCAD 2011, we can see more usage of this vertex. Polylines mid vertex has several more options.
Now you do not need to activate PEDIT and can add vertex quickly, and even convert the segment to arch! Well, you can also convert an arch segment to line by the way...
But the most fun of the vertex enhancement is for hatches.
Stretch will simply move the hatch from original position. See the other three options! You can define the origin, angle, and scale on the fly!
Working with Edges
What about edges? You can modify the edges without having to modify the whole object. In the sample below, you can create a parallelogram from a rectangle. Simply move the edge.
You can also scale the edge.
Is there any other way you use the subobjects that we may miss?
And which subobject you use the most, and why do you like it?
You will find this tip and more on Edwin’s CAD-Notes website, http://cad-notes.com/
If you would like to submit a guest post please Email Me for details.
Cheers,
Shaan
Bless its heart. The UCS icon has been through years of neglect with only occasional costume changes. Several versions ago they put it on WeightWatchers® which made it much less clunky. 
Then somewhere along the line they added the Properties option of the UCSICON command. [View tab
Coordinates tab
In AutoCAD 2012, however, they have empowered the icon itself with multi-function grips! Yes, the RTUCS command is still around (Real Time UCS, covered nearly 7 years ago in 
At this point, that is my most favorite feature of AutoCAD 2012, based on frequency of use and time saved. Next month, we'll look at the new associative Array command.