# Obtain Area and Mass Properties Information

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 multiple 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.

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 calculated as though a straight line connects the start point and endpoint.*AutoCAD 3D solids.*Total 3D area for the object displays.

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.

With the MASSPROP command, you can analyze 3D solids and 2D regions for their mass properties including volume, area, moments of inertia, center of gravity, and so on. In addition, the result of the computations can be saved to a text file.

- While a combined area displays, enter
*s*(Subtract). - Do one of the following:
- Specify points to define the area you want to subtract. Press Enter.
- Enter
*o*(Object) and select the objects you want to subtract.

The running total of all areas updates and displays as you define new areas.

- Press Enter to end the command.