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    By Dennis Collin

    In previous blogs I outlined easy ways of measuring areas using the properties palette and Quickcalc to determine areas. Although this works well, there is a margin of error due to the fact if a drawing is updated the area text will also need to be manually amended to the same value.

    However, for many years now AutoCAD has supported fields, these are linked annotation objects that can show automatically certain information such as filenames, author, dates as well as specific AutoCAD properties like length and areas.

    Fields can be added to both text and block attribute information which will have a dynamic link to the original object’s properties. In the example below some multiline text has been linked to a hatch object which is my preferred method to determine areas within AutoCAD.


    This process is about as quick as previously described methods and is easy to accomplish. Create a Mtext object as normal, on an appropriate layer, with a background mask and within the editor type in a prefix e.g. Area. The field is added by clicking on the highlighted button choosing relevant target field options.


    Fig 1. Selecting the field function within the AutoCAD Multiline Text Editor

    The field property options are displayed in the image below. The category should be objects. The field names, object, marked 1. The object type is determined by user selection (2 & 3), in this example a hatch object. The linked property is area which is then configured further by the additional formatting options (4 & 5).


    Fig 2. Setting field source and formatting options

    Once this is done, confirm and the linked area text will display as shown. Add a m² suffix and the note is complete. The grey background around the value indicates it’s a dynamic link as opposed to a manually entered value.

    Adjusting the area of the hatch will update the value once the file is saved.


    Fig 3 Room area changing automatically after enlarging a room.