If you have AutoCAD® 2000 or higher, you have access to one of my all time favorite commands: QDIM, for Quick Dimensioning. If you're still churning out your dimensions one at a time you simply must try this great timesaver.

The basic concept is simple—you window the group of objects you need to dimension, select the type of dimensioning you want, and place the displayed dimensions in the proper location. Super Simple! This command is especially powerful at knocking out baseline and continuous dimensions, but it also does a great job dimensioning a series of arc or circles (holes). Let's take a look at the actual QDIM command. If you'd like to follow along, open up a drawing that's in need of some dimensioning.

Command: QDIM
Select geometry to dimension: Select the objects you wish to dimension
Select geometry to dimension: Enter
Specify dimension line position, or
[Continuous/Staggered/Baseline/Ordinate/Radius/Diameter/DatumPoint/Edit]
<Continuous>:

After you select the objects you wish to dimension, you can choose between a variety of different types of dimensioning. I'm fairly certain you understand Continuous, Baseline, Ordinate, Radius, and Diameter dimensioning so I'll focus on the other options. DatumPoint enables you to indicate a new datum point for baseline or ordinate dimensioning. Staggered is a head-scratcher, and since the help file does nothing to explain it to you, let's provide a brief explanation.

Many dimension standards run into the need to dimension smaller distances with a larger dimension as shown in Figure 1. The dimensions ultimately end up stacked on top of each other with their text staggered from left to right as you ascend the stack.

Figure 1: Many dimension standards run into the need to dimension smaller distances with a larger dimension.

The Edit option gives you more control over the final dimensioning outcome. Here you will find that you can easily add or remove the various selected points QDIM is going to use to determine the final dimensions. Figure 2 provides an example of the various points that show up when you select Edit mode. From the selection set you simply select the points you wish to add (or remove).

Figure 2: Simply select the points you wish to add (or remove).

Once your dimensions are placed in your drawing, you can easily go back and change your dimensions from one type to another. Perhaps you selected Radius but wish you'd selected Diameter. Simply go back into QDIM, reselect the objects (and the dimensions), indicate the new dimension type and proper placement and Voila—they magically update!

I have some good news and some bad news here (get ready for a big plug for the AutoCAD Extensions!). These QDIM dimensions are not part of the new AutoCAD 2002 smart associative dimensions. Clearly that's the bad news. The good news is that the latest Extension includes a utility that makes the QDIM dimensions associative (hoorah!). So after you've become addicted to this awesome command (and you will become addicted), if you want them to be extra smart and truly associative, check out the Subscription program and get your hands on the latest Extension!

Until next month, happy AutoCADding!