How to use fields in AutoCAD drawings

Fields are dynamically linked properties and they update automatically when the object property changes.

An example of field is date.

When you add date filed in AutoCAD drawing it will show the current date always.

Similarly there are several other fields that you can use in your drawings.

Most of these fields are used in blocks containing attributes, title block texts and more.

Sheet set is another area where fields are extensively used.

In fact in our AutoCAD sheet set course we have created label blocks, callout blocks and title blocks all using fields.

So, in this article I will share a specific use cases of fields in AutoCAD that I found interesting, it's for displaying area dynamically.

Area Field

Let's assume we want to show the area of a room in floor plan in a way that the area updates automatically when the drawing updates.

For that we will add area field.

I will use the following drawing for this example, here I have already deactivated the door to make correct room boundary.

Later we can bring back the door after adding the field.

We will add the area filed in the room that you see here.

To do that we will start with text style as fields tend to take the style of your current text style.

Type ST press enter to start the text style window.

In the text style window select "Simplex" font (or any other font if you want) and for our example I am selecting the text size of 6" which will look normal on my current drawing.

Now Click Apply and close the text style window.

The next step is making a boundary around the room and for that I will use BOUNDARY command.

Type BOUNDARY on the command line and press enter.

Select Polyline from the boundary option as shown in the following image and click on the pick points button.

Now click inside the room anywhere and press enter to create the polyline boundary.

As next step type FIELD on the command line and press enter.

Select objects from the field type dropdown and then select Object from the next list as shown in the following image.

Click the box in the object type section of the field window and then click the boundary we created in the previous step.

The filed window will open up again with more options added to it.

Select area from the "Property" panel and select the format that you want from the "Format" panel.

Click OK and then click inside the room to place the field text.

I will also "unhide" the room door that was hidden to make the boundary and the final room with filed will look like the following image.

Field Settings

By default, field will inherit properties of current text style and it will also show a grey background. 

This grey background will only remain visible in the drawing area and it will not appear when printed. 

Although the grey background helps in distinguishing fields from simple Mtext you can remove this background as well.

To hide the field background type OP on the command line and press enter, this will open options window.

Select User Preferences tab and uncheck the radio button in the 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.

Other settings

When the object associated with the field is changed the field updates itself automatically.

But sometimes these changes won't show up in the drawing area.

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 the 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 set the proper value of FIELDEVAL to manage update settings as shown below.

• The value of 0 won't update the filed.
• 1 will update it when file opens
• 2 will update when file is saved
• 4 will update when you plot your drawing
• 8 will update on e-Transmit
• 16 will update when drawing is regenerated.

Summary

Area command was just one example where filed can be used and there are several cases where fields can be used to make your drawing more intelligent.

Specially in sheet sets it's an indispensable tool.

If you have questions related to filed let me know in the comment section down below.