By Dennis Collin
Deriving area information is frequently required from drawings over a whole range of disciplines. One method of obtaining this information can be obtained from the area command under the inquiry panel on the AutoCAD ribbon.
Fig 1. Locating the classic Area command
This command can obtain the information in a variety of ways, however, the command is a rather old, slow and inefficient way of measuring areas compared to more modern methods.
My personal preference is to make use of the Properties palette, polyline and hatch objects. Drawing these elements on appropriate layers, means that the information can be displayed or hidden as desired. When area information is required, simply select the object in question, bring up the property palette, by right clicking or using the ‘Ctrl+1’ keyboard shortcut. The area value will be displayed within the geometry panel using whatever units have been specified in the drawing’s template.
Fig 2. Measuring the area of a stairwell within a building plan
Polylines are useful for determining gross areas and perimeter length, but if a net area is required hatch objects can be used instead. In the example image below, we can measure the net area of a room excluding the area filled by supporting structural columns. Hatches also have an added benefit that if multiple areas are selected, AutoCAD will automatically add the areas and show the total under the cumulative area field below the individual hatch area field.
Fig 3a. Determining Net Area of a room, less column areas. Note the cumulative property below the main area field.
Fig 3b. Selecting multiple hatches gives a cumulative area total.
By default, AutoCAD will show the area in the standard drawing units, in this example millimetres. However, whilst in construction, lengths might be needed to display as millimetres, areas tend to be reckoned in square metres. This can be achieved by ‘moving’ the decimal point six places to the left, but this can easily result in errors. In a future blog I will show how this can be done more reliably with the possibility of mixing units and showing areas in square feet instead.