Tipster Vladislav Bronin presents some uses for fields in AutoCAD files.
"Reading CAD Tip No. 4153, 'Auto-Update Viewport Scales in Paper Space,' reminded me of a few good things the fields can do.
"Case 1: I have a big drawing divided into smaller sections, several of which contain similar texts. It always creates mistakes; you can modify the text in one location, but forget that you have the same phrase somewhere else that also has to be modified. Fields can resolve this issue. After the first text was typed in, copy it somewhere close by. Then instead of the identical typed text, insert a field. Reference this field to an object, and as an object select the text you just have copied. In field options select 'Context' and choose the way it will be represented on the screen (i.e., capital, sentence, or small letters) — that's it. Now place this duplicate in all locations you find it necessary. Once the original text is revised, all its duplicates will update automatically.
"Case 2: Fields and formulas. This could be useful if you have to calculate something, such as the slope of a line from point A to point B based on its length (a useful calculation for plumbing and site services designers). Suppose point A of the line has coordinate y (some numeric value), and the line slopes with x% downgrade. Then, when typing text for the point B, do the following: Create a 'temporary' text. Insert a field, choose Object, and point to the line in question. In options, select 'Length'. Once this is all done, copy the entire content of the field expression at the bottom of this pop-up screen. This information will be used later on. Now, create a new text and insert a field. Choose Formula. In the formula, type the equation to estimate the coordinate of point B; i.e., Y-X/100*L. Here, instead of L, paste the expression you have copied from the 'temporary' text. If everything is done properly, you will see that in this location will appear a field showing the length of the line. And in the future, if the length of that line changes, the coordinate of point B will update automatically."
Notes from Cadalyst tip reviewer Brian Benton: Fields are extremely useful. A field can be inserted into any text-type object. That means multiline text, single-line text, dimension text, annotated text, leaders, block attributes — anything with text. Fields can read and display information from almost any type of object in AutoCAD. They can also display sheet set data, which can be assigned to multiple files. Otherwise fields can only read data from the file they are in, so keep that in mind.