Almost all drawings except schematics have dimensions. Obviously, the purpose of dimensions is to show accurate measurements. So what do you do to create accurate dimensions?
Create a dimension style
You should always use a customized dimension style for your dimensions. I have a tutorial, “Create an architectural dimension style,” which you’ll find useful even if you aren’t creating architectural drawings. That’s because the tutorial takes you through the entire process of creating a dimension style.
Part of the process of creating a dimension style is creating a text style for the dimension’s text. For more, go to “How to create a text style for a dimension.”
Create a dimension layer
Dimensions should always be on their own layer, using a color that contrasts with the objects you are dimensioning. You don’t want your dimensions to be confused with your model! Call the layer Dimension or DIM–something like that.
Set up running object snaps
For accuracy, you should use object snaps, especially if you aren’t dimensioning an entire object. So, set up the ones you want. One way is to right-click the Object Snap (or OSNAP) button on the status bar and choose the object snaps that you want. If Object Snaps aren’t on, click the Object Snap button on the status bar.
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Get set up for dimensioning
On the Home tab, in the Layers panel, choose your dimension layer from the Layer drop-down list.
Also on the Home tab, expand the Annotation panel, and choose your style from the list of dimension styles. (You can also find this list on the Annotate tab.)
Center the object that you want to dimension in the drawing area so you won’t run out of room.
Go to Home tab> Annotation panel or the Annotate tab> Dimensions panel. In either location, you’ll see the drop-down list of dimension types. For this exercise, choose Linear. This starts the DIMLINEAR command.
Follow these prompts.
Specify first extension line origin or <select object>: Use an object snap to specify where you want the dimension to start.
Specify second extension line origin: Use an object snap to specify where you want the dimension to end.
Specify dimension line location or
[Mtext/Text/Angle/Horizontal/Vertical/Rotated]: Move the cursor to where you want the dimension line to be and click.
If you are dimensioning an entire object, such as one of the vertical lines in this model, at the first prompt press Enter to select the object. This ensures an accurate result.
How do I know if I’m dimensioning the right coordinate?
When you are not dimensioning an entire object, and one of the points (the beginning or end of your linear dimension) is at the endpoint of another object, how do you ensure that you are specifying the endpoint of the object you’re dimensioning and not the endpoint of the other, touching object? For example in the model above, how do you ensure that the endpoint marked is the endpoint of the horizontal line that you want to dimension and not the endpoint of the rising line?
First, what difference does it make?
Dimensions are associative, which means that they are connected to the objects they dimension. If you edit the object, you want the dimension to adjust accordingly. But if you specify the wrong endpoint, you may not get the right result.
So when specifying an endpoint, place the cursor slightly off the endpoint of the object you are dimensioning and let the object snap specify the coordinate for you.
Watch the video to see how to place the cursor to get an accurate linear dimension.
What ideas do you have for creating accurate linear dimensions? Please leave a comment!