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Understanding Basics of Dimension Style Settings

Post a Comment Nov-10-2008 | Posted by Erhan Toker | Printable Version | Level |

Probably AutoCAD users spent most of their time for dimensioning. Even though new innovations come in each version, dimensioning and its settings is still a difficult subject for users. In this article, I will talk about dimensioning settings in detail.

Fig. 1

We can reach the dimensioning style main window, seen in Fig.1, by DDIM command or Format/Dimension Style… menu. On the left side of this window, there is a list of dimension styles existing in the drawing. In the middle, there is a small sketch, which shows, and on the right side, there are buttons. Now, let’s explain these important settings by examples, starting with creating a new dimension style. In order to initialize our new dimension style, click New… button on the right side.

Fig. 2

Let’s name our dimension style, ARCHITECTURAL-50, and press “Continue” button. If Start With listbox is left as ISO-25 as seen in Fig.2, then all the settings will inherit from this dimension style. However as we will deal with all settings this is not important for this time. First tab on the left is Lines (Fig.3)

Fig. 3

In this window, there are settings for the line members of the dimensioning object. There are settings for color, linetype, lineweight (line thickness) and Baseline Spacing (Fig.4).

Fig. 4

Extend beyond thicks (sets how much the dimension line will go further after the sidelines if architectural cut line is used) and Supress. With help of Supress, it is determined which one of the dimension lines will be drawn. It used to be important for the old printers with pen. The reason is that, in case of overlapping dimensions, it is not desired for the rapido pen to draw twice. In such a case, one of the dimension feet is not drawn. Extension Lines part, in the lower left part, includes the settings about the two feet of dimension. Here, Extend Beyond Lines is about how much further the foot line will go up after the dimension line. Offset From Origin adjusts how far the foot lines will start away from the objects that are dimensioned.

Fig. 5

In the Symbols and Arrows tab, there are settings for dimension arrows. For architectural dimensioning style, we chose Architectural tick. Of course, we are leaving Leader as default arrow shape, for defining the end of dimension lines as arrows. For the dimensions given in this window, we will not do any change now. According to the drawing unit and printing scale, we will make this decision later.

Fig 6

In Text tab, we can make the settings about the text part of dimension. I use the style named ARCH, which I prepared before. If you don’t have any style you have prepared, you can immediately prepare one by clicking the … button which is just on the right side of the listbox. Here, the important settings are in the Text Placement part. For architectural dimensioning, dimension text should be on the top of dimension line. For this aspect, vertical layout should be Above, and, horizontal should be Centered. For technical drawing style, you can adjust vertical layout as centered.

Fig. 7

Settings for scale and text placement can be made in Fit tab (Fig.7). In this part, it is determined how the dimension text will be placed in between the two feet of the dimension object. This setting is for the case where the text occupies more space than the dimension width. Wall width in architectural drawings is a typical example for this (Fig.8).

Fig. 8

Scale for dimension part is the most important part especially for the scaled drawings. Text height, arrow length, extension distances that you have prepared before will all be multiplied by the Use overall scale value. Thus, if you write here 3, then all of our dimensioning arrows and texts will enlarge 3 times. You can adjust this value according to the However, if you are taking printout from by using LAYOUT, and you are adjusting the print-out scales with Paperspace Scaling (like ZOOM – 1/20XP), then you have to mark the Scale dimensions to layout option button.

Fig.9

Number units and leading zeros in numbers are set from the Primary Units tab. In Linear dimensions, Precision determines how many digits will be used after the “.”. As a matter of fact, precision required in cm drawings is ½ , which means 0.5 cm. In order to adjust this we make Round off set to 0.5. With Prefix and Suffix settings, we can determine the use of additional texts before and after the dimension text (i.e. mt, cm etc.). Generally, these settings are left blank. Measurement scale is totally different from the overall scale, which we have written previously. AutoCAD automatically takes the measurement between the two points that we pick while creating the dimension itself. Thus, this value measured is multiplies with the Measurement scale value. If you are making a one to one scaled drawing, which is the correct thing to do (as mentioned in Orhan’s Understanding scale concept and units in Autocad… article), this value should be left as 1. However, sometimes we make 2/1 or 5/1 scaled drawings by opening detail windows in LAYOUT. In such a case, By adjusting this value to 0.5 or 0.2, you can mark the Apply to layout dimensions only option. This option will directly affect only the dimensioning that we made on the LAYOUT. In Zero suppression, we can adjust the zeros in the number as leading ( zeros before dot) and trailing ( zeros after dot ). Similarly, there is an Alternate units (for example sometimes we want to use metric and imperial units together in the same drawing) tab. Difference is that we should mark that we want to use alternate units. For international projects, this may come in handy. Tolerance tab is used for adjusting dimension tolerances in mechanical drawings and includes the similar settings.

After we complete our settings, in order for the changes to take effect, we must choose our new style form the main window (Fig.1) and press Set Current button. If there are still some dimension lines that do not change, by entering DIM command in the command line, you can use the following:

Dim: UPDATE

Finally; as you make any dimensioning, you will see that that there are some small points in the points you have picked for dimensioning. If you enter PDMODE in the command line and set to 3, you can see these small points better by setting these points with X( Point Style = X ). These are intermediate points that AutoCAD uses for linking the dimension objects with objects that belong to the drawing. They are drawn in Defpoints layer. As this layer is a special layer, it is not sent to plotter. However, some users make their drawings in this layer, so they can not take any print-out. Reason for such a mistake is that.