AutoCAD Fields Tutorial: Dynamic Text and Title Blocks
A field in AutoCAD is text that reads its value from the drawing and updates itself when the data changes. Instead of typing an area, a sheet number or a file name and hoping you remember to retype it, you insert a field once and let AutoCAD keep it current. This tutorial shows you how to insert fields into text, tables and attributes, how to build an automated title block, and what to check when a field shows the wrong value.
TL;DR
Fields are dynamic text: right-click inside MText, a table cell or an attribute definition and choose Insert Field.
Object fields (area, length, radius) update when the object changes. Sheet set fields feed title blocks.
For title blocks, put the field in the attribute definition’s Default value, never only in an inserted block’s Value.
The FIELDEVAL system variable controls when fields refresh. The Date field is the exception: it only updates with UPDATEFIELD.
If you see ####, the field is invalid. If you see ----, it has no data.
Table of Contents
What an AutoCAD field actually is
AutoCAD’s documentation describes a field in text as an instruction to display data you expect to change during the life of a drawing. When the field updates, the latest data is shown. That data can be the area of a closed polyline, the length of a line, the file name, the plot scale, a sheet number or a custom property you define yourself.
Fields can go into most text-bearing objects. According to Engineering.com’s AutoCAD fields tutorial, that includes block attributes, tables, leaders and dimensions. In practice, you will meet them in four places:
MText and single-line text, for room areas, notes and revision references.
Tables, for schedules that should follow the geometry.
Block attributes, for title blocks, tags and callouts.
Sheet set callouts and labels, for view titles and sheet numbers.
A field usually shows with a light grey background on screen. That background does not plot. If it bothers you, the FIELDDISPLAY system variable turns it off, but most drafters leave it on because it makes dynamic text easy to spot.
Insert your first field: a room area
The classic first exercise is an area label that follows the room outline. You need a closed polyline for it.
Draw a closed polyline for the room, or run BOUNDARY inside an enclosed area and choose Polyline as the object type to generate one.
Start the MTEXT command and drag a text box beside the room.
Right-click inside the editor and choose Insert Field. (You can also press Ctrl+F in the in-place editor.)
In the Field dialog, set the Field category to Objects and the Field name to Object.
Click the select-object button, then pick the polyline.
Under Property, choose Area.
Choose a Format. For metric work in Ireland, set the units to square metres, a precision of two decimals, and add a suffix such as m² if you want it shown.
Click OK, then close the text editor.
Now stretch a vertex of the polyline and run REGEN. The number changes. That is the whole principle: the text is attached to the object, not to your memory.
Unit conversion for areas
Drawings drawn in millimetres give you an area in square millimetres, which is not what anyone wants on a floor plan. In the Field dialog, the Format section lets you pick a Conversion factor. For mm² to m² the factor is 0.000001. Set it once, copy the field text, and reuse the same MText for every room by editing only the object it points to.
Length, radius and other properties
The same Object field works for a line (Length), an arc (Arc Length, Radius), a circle (Radius, Diameter, Circumference) and many others. The Property list changes depending on what you pick. If a property you expected is missing, you have probably picked the wrong object type, for instance a hatch where you meant its boundary.
Fields in tables and formulas
Table cells accept fields directly. Double-click a cell, right-click and choose Insert Field, exactly as for MText. This is a quick way to build a simple room finishes list whose area column follows the plan.
Tables also support formulas. In a cell, right-click and choose Insert Field, then pick Formula to add cell values or sum a column. If you want to total two areas, you build a formula, then insert an Object field inside it for each polyline. It is fiddly, so label each area clearly before you start and test with a pair of rectangles you can check mentally.
Fields in title blocks
This is where fields save the most time, and where most mistakes happen. A title block that needs retyping on every sheet breeds errors: a wrong sheet number, an old revision, a stale project name.
The approach described in the Autodesk AutoCAD blog on automating title block data is to replace typed values with field codes. You can use the predefined codes for items like the current date, sheet number and drawing name, or custom sheet set properties you create yourself.
The short version of the workflow:
Create a sheet set and add a sheet to it, so your title block lives in a drawing that is a real sheet. The blog explains that you then see at once whether you picked the right field, because it displays live data.
Open the title block as a block in the Block Editor (BEDIT).
Create attribute definitions with ATTDEF for each item: project name, client, sheet title, sheet number, revision, drawn by.
Set the Default value of each attribute to a field. Use the three-dot button beside Default to open the Field dialog.
Choose SheetSet as the field category and pick the relevant property, such as SheetNumber, SheetTitle or a custom property.
Save the block and use ATTSYNC or reinsert it so existing instances pick up the changes.
If you want a fuller walk-through of block and attribute setup for drafting offices, our guide on setting up an AutoCAD title block with fields first goes step by step, and our article on fixing ATTDISP problems and duplicate tags covers the attribute side in depth.
The mistake that breaks automation
The most common error is putting the field in the wrong place. Autodesk’s own guidance is to edit the attribute definition so the field sits in the Default value. Fields entered into an inserted block’s Value, for instance through the Enhanced Attribute Editor, BATTMAN, REFEDIT or by double-clicking the block, are described in the same Autodesk blog post as a way to lose the automation when the block is reinserted or updated. Fix the definition, not the instance.
Contextual fields need attributes
Some fields are contextual: their value depends on the layout or space where they sit. Autodesk’s page on contextual fields in blocks and xrefs explains that for a title block you should insert such a field as an attribute definition rather than as plain text inside the block. Otherwise the same block placed on different layouts will not display each layout’s own value. Typical contextual fields include the sheet number, layout name and plot scale.
Give missing data a visible placeholder
When you define custom properties, give them a default of ----. AutoCAD already shows ---- for a field without data, so an unfilled property stands out on screen and in a plot preview, rather than printing as a blank. Autodesk’s page on template projects is aimed at AutoCAD Architecture, but it makes the broader point that a well-planned template automates office standards and speeds up starting a project.
When fields update: FIELDEVAL
Fields do not recalculate continuously. The FIELDEVAL system variable decides when. It is saved in the drawing and has an initial value of 31. The value is a sum of bitcodes:
Bitcode | Fields update when you… |
0 | Never update automatically (manual only) |
1 | Open the drawing |
2 | Save the drawing |
4 | Plot |
8 | Use ETRANSMIT |
16 | Regenerate |
Add the numbers for the combination you want. 31 is 1 + 2 + 4 + 8 + 16, so everything is on. If you want fields to update only on opening and plotting, set FIELDEVAL to 5.
To force an update at any time, run UPDATEFIELD and select the field, or type ALL. You can also select the text, right-click and choose Update Field.
The date field is different
The Date field does not follow FIELDEVAL. According to Autodesk’s FIELDEVAL page, it updates only through the UPDATEFIELD command. That surprises people who use a date field as a “last printed” stamp. If the date matters on issue, run UPDATEFIELD before plotting, or build it into your plot routine.
Troubleshooting fields
What you see | Likely cause | What to do |
#### | The field is invalid, for example the referenced object was deleted | Edit the field and pick the object again |
---- | The field has no data, such as an empty sheet set property | Fill in the property in Sheet Set Manager |
Old value after you edit geometry | FIELDEVAL does not include regeneration, or the drawing has not regenerated | Run REGEN or UPDATEFIELD |
Title block shows the same value on every layout | Field was inserted as plain text, not as an attribute definition | Rebuild it as an attribute with a field default |
Block instances lose their fields after an update | Field was set in Value, not Default | Edit the attribute definition, then ATTSYNC |
If a drawing still refuses to update after those checks, the Autodesk Community thread on fields not updating after REGEN shows that this can happen in large files even with FIELDEVAL at 31, and that updating the source field individually may be the practical workaround. Treat that as a user report, not an official fix, and keep a backup before you rebuild anything.
When you test a new title block, test it on a real sheet in a sheet set, not only in the template file. You get live feedback on whether each field reads the right property before you save the template.
A worked example: a small residential issue set
Suppose you are issuing four sheets for a house extension: site plan, ground floor, first floor and elevations.
Create a sheet set called after the project and fill in the project name, client and address as sheet set properties.
Build one title block with attributes for project name, client, sheet title, sheet number and revision. Set every Default to the matching SheetSet field.
Add custom properties for “Drawn by” and “Status”, defaulting to ----.
Create the four sheets. Each pulls its own number and title automatically.
Add a callout block with a view title field, so the labels under each viewport follow the view name.
Before plotting, run UPDATEFIELD, choose ALL, and check that no ---- or #### remains in the plot preview.
The result is that renaming a sheet in the Sheet Set Manager updates the title block and any list of sheets, with nothing retyped. If the client changes the project name, you change it once.
The same logic carries across to Revit, where title block data is managed differently. In Revit, custom title block fields use shared parameters categorised under Sheets for sheet-specific data or Project Information for project-wide data, added to the title block family as labels. If you work in both packages, our guides to the Revit title block and Revit project information show the equivalent setup.
Our perspective: fields are a habit, not a feature
We teach Revit and AutoCAD to architects and technicians, and the pattern we see is consistent. People learn what a field is in ten minutes and then don’t use it for months, because a typed value is faster today. The cost shows up on issue day, when a drawing goes out with the wrong revision or a room area that no longer matches the plan.
Our advice is to start small and make it a rule. Every area label gets a field. Every title block value that exists elsewhere in the project gets a field. Build that into the template once and no one on the team needs to think about it again. The second rule is to test in the place where the field will live. A field that works in the template file and fails on a sheet has cost someone an afternoon, so we always check on a real sheet before signing off a template.
The third rule is the one we repeat most: change the definition, not the instance. Most of the “my fields vanished” questions we see trace back to someone editing an attribute value on a single block. It feels quicker. It is the reason the automation fails later.
— Steve
Where to go next
Fields sit between drafting and drawing management, so they reward a solid grounding in blocks, attributes, layouts and templates. If you want that grounding in a structured form, our AutoCAD Training course takes you from beginner to expert through project-based work, costs €79 as a one-off payment, and comes with trainer support and lifetime access to the materials. For deeper block work, our article on AutoCAD dynamic blocks and the errors to avoid is a good companion to this tutorial.
FAQ
How do I insert a field in AutoCAD?
Open any text editor (MText, a table cell or an attribute definition), right-click and choose Insert Field. Pick a category and field name, set the format, and click OK. Per Autodesk’s documentation, this works in almost any text object.
How do I use fields in an AutoCAD title block?
Create attribute definitions in the title block and set each Default value to a field, usually a SheetSet field. Work from a drawing that is a sheet in a sheet set, so you can see live values. Edit the definition rather than an inserted instance, or the fields can be lost when the block is reinserted.
Why is my AutoCAD field not updating?
Check FIELDEVAL first. At 31, fields update on open, save, plot, ETRANSMIT and regeneration. Then run UPDATEFIELD, and remember that the Date field only updates through that command. A #### result means the field is invalid, while ---- means the source has no data.
What does FIELDEVAL 31 mean?
It is the default, and it is the sum of 1, 2, 4, 8 and 16. Each number switches on automatic updating for one event: opening, saving, plotting, ETRANSMIT and regeneration. Lower the value if you want fewer automatic updates, for instance in very large drawings.
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