At any rate, my favorite tips for AutoCAD are almost always short and sweet, so, I'm going to post them here in little bite-sized chunks.
There are a few different ways to go about selecting entities to examine or modify, depending on your specific needs at the time. If you were to select every single entity in a drawing, when you bring up the Properties palette, you notice that some properties are not available for editing. That is because different entity types do not all have the same properties. You have to filter out dissimilar entities, so that you can access the controls you need. The following paragraphs contain four different ways of creating selection sets, select your favorite!
One of the easier ways to get a group of objects together for mass editing would be through the Isolate command, available on the Layers panel of the Home tab. You select an object or objects on the layers you want to see, and this command will hide the remainder of the layers for you. You can also start and reverse the command by typing in LAYISO and LAYUNISO.
A more precise method for selecting objects is Quick Select. You can find this command on your right-click menu, on the top of the Properties palette, or by typing QSELECT. In the command’s dialog box, you see that you’ve got a couple more options to get more specific in your object selection. You can control what portion of your drawing the selection will draw from, which types of entities are included in your selection set, which properties the desired objects have, and what values you want to include or exclude. Say, I want to grab all Polyline entities whose layer color is <> not equal to BYLAYER. I might not want to grab all entities in the drawing and set them all to bylayer, because I might have some annotation in the drawing that needs to remain a distinct color for some temporary reason. Or, perhaps I want to grab all Text on layer A-Rm-Num that is less than 9” tall, I can quickly and easily do that here.
If you use the Filter command, bringing up the Object Selection Filters dialog, you see how precise you can be in selecting objects, and you can even save the filter criteria for future use.
Another, more recent, addition is the Select Similar command. It has been available in vertical products for many years, and I was thrilled when it was finally added to vanilla AutoCAD. If you’re using release 2010 or earlier, you can find lisp routines which will provide this functionality. There is code available in the forums and on myMistress of the Dorkness blog, along with instructions on adding it to your right-click menu. I like the way it works, being a part of your shortcut menu, because you don’t have to interrupt your workflow by using a dialog box or moving out of the drawing area to click a button. Type SELECTSIMILAR then SE to access the Select Similar Settings dialog box and dictate which criteria you prefer to gather your selection by.