Obtain Area and Mass Properties Information (Concept)

You can obtain the area, perimeter, and mass properties defined by selected objects or a sequence of points.

You can calculate the area and perimeter of a sequence of points. You can also obtain the area, perimeter, and mass properties of any of several types of objects.

Use Commands to Calculate Area

With the MEASUREGEOM and AREA commands, you can specify a series of points or select an object to calculate area. If you need to calculate the combined area of mutiple objects, you can keep a running total as you add or subtract one area at a time from the selection set. You cannot use window selection or crossing selection to select objects.

Total area and perimeter are saved in the AREA and PERIMETER system variables.

In addition to area, with the MEASUREGEOM command, you can obtain geometric information from objects such as distance, radius, angle, and volume.

Define an Area

You can measure an arbitrary closed region defined by the points you specify. The points must lie on a plane parallel to the XY plane of the current UCS.

Calculate the Area, Perimeter, or Circumference of an Object

You can calculate the enclosed area and perimeter or circumference of circles, ellipses, polylines, polygons, regions, and AutoCAD 3D solids. The information displayed depends on the type of object selected:

Circles. Area and circumference display.
Ellipses, closed polylines, polygons, planar closed spline curves, and regions. Area and perimeter display. For wide polylines, this area is defined by the center of the width.
Open objects such as open spline curves and open polylines. Area and length display. Area is calcuated as though a straight line connects the start point and endpoint.
AutoCAD 3D solids. Total 3D area for the object displays.

Example: How Various Areas Are Calculated

Combined Areas

Calculate Combined Areas

You can calculate the total area of multiple areas by specifying points or by selecting objects. For example, you can measure the total area of selected rooms in a floor plan.

Subtract Areas from Combined Areas

You can subtract more than one area from a combined area as you calculate. For example, if you have calculated the area of a floor plan, you can subtract the area of a room.

Example: Subtraction of Areas from a Calculation

In the following example, the closed polyline represents a metal plate with two large holes. The area of the polyline is first calculated and then the area of each hole is subtracted. The area and perimeter or circumference of each object displays, with a running total after each step.

The command prompt sequence is

Command: area

Specify first corner point or [Object/Add/Subtract]: a

Specify first corner point or [Object/Subtract]: o

(ADD mode) Select objects: Select the polyline (1)

Area = 0.34, Perimeter = 2.71

Total area = 0.34

(ADD mode) Select objects: Press ENTER

Specify first corner point or [Object/Subtract]: s

Specify first corner point or [Object/Add]: o

(SUBTRACT mode) Select objects: Select the lower circle (2)

Area = 0.02, Circumference = 0.46

Total area = 0.32

(SUBTRACT mode) Select objects: Select the upper circle (3)

Area = 0.02, Circumference = 0.46

Total area = 0.30

(SUBTRACT mode) Select circle or polyline: Press ENTER

Specify first corner point or [Object/Add]: Press ENTER

You can also use REGION to convert the plate and the holes to regions, subtract the holes, and then use the Properties palette or the LIST command to find the area of the plate.

TipUse the QuickCalc calculator to convert from one system of area units to another. For more information, see Use the QuickCalc Calculator.