Fields are special texts which update itself automatically when its linked object or property changes. For example, you can add a field which represents the area of an object and when the area changes field updates itself automatically.
Fields are extensively used in the Sheet Set and they can be used to add intelligence to the title block and layouts of the sheet set. Using Fields information in the sheet set can be interlinked properly keeping the data correct and updated even when changes are made in the drawing.
In this article, I will explain the use of Fields in AutoCAD drawings using a field that represents the area of a geometry.
Make a circle in the drawing area and type FIELD on the command line and press enter, now select objects from Field category drop down menu and select Object from Field names panel. Now click on selection box near Object type box, and select the circle from drawing area.
You will notice that the Property panel will show all properties related to the circle. Select area from this list and select the format in which you want the area to represent. Click ok to close the Field window and place the area field inside the circle.
In the example above if you change the area of the circle, the associated field will get updated to reflect the new area.
By default, field will inherit properties of current text style and it will also show a gray background. This gray background will only remain visible in drawing area and it will not appear when printed. Although the gray background helps in distinguishing fields from simple Mtext you can remove this background as well.
Type OP on the command line and press enter, this will open options window. Select User Preferences tab and uncheck the radio button in fields panel as shown in the image below. Click ok to save the changes and exit the window.
You can also toggle the visibility of background from fields using FIELDDISPLAY system variable, where 1 makes the background visible and 0 makes it invisible.
When the object associated with the field is changed the field updates itself automatically but in order to display that updated information you need to regenerate the drawing using RE command.
You can also use UPDATEFIELD to manually select the fields and update them, the UPDATEFIELD command does not update data field and you need to update it manually.
The FIELDEVAL system variable can be used to automatically update fields in a drawing. You can see more on this on this knowledge network page.
Do you have questions related to this tip? Let me know in the comments below.