Information
Review date: 2011May20
Applies to:
,ZWCAD 2010,ZWCAD 2011,
May 20, 2011
You can calculate the area and perimeter of a polygon based on a series of points you specify or enclose with a circle or closed polyline. You can also determine the area of several combined objects and add or subtract the area of one or more objects from a total combined area.
Calculating areas defined by points
You can find the area and perimeter of any closed region by specifying a series of points. The program calculates the area and perimeter of the space that is enclosed by an imaginary polygon consisting of straight line segments connecting each point.

To calculate the area defined by points you specify
Choose Tools > Inquiry > Area.
Specify the first point.
Specify the second point.
Continue specifying points in sequence to define the perimeter of the area you want to measure.
To complete the calculation, press Enter.
The area and perimeter of the region you defined are displayed.
Inquiry toolbar
Command line AREA
Select the points (A, B, C) that form a polygon. The area and perimeter of the region are then calculated. 
Calculating areas of closed objects
You can find the area of any closed object. In addition, the program calculates either the circumference or the perimeter of the object, depending on the type of object you select.
To calculate the area of a closed object
Choose Tools > Inquiry > Area.
On the command line, type e (entity).
Select the closed entity.
Inquiry toolbar
Command line AREA
Calculating combined areas
You can find the total area of several combined regions by specifying points or by selecting objects. You can also subtract the areas of objects or polygons from a running total.
To add areas to calculate a combined area
Choose Tools > Inquiry > Area.
On the command line, type a (add).
Using one of the following methods, identify the first area:
Specify points defining a polygon, and then press Enter.
Type e (entity), select the entities you want to add, and then press Enter to complete the calculations.
To complete the command, press Enter.
Inquiry toolbar
Command line AREA
To subtract areas when calculating a combined area
Choose Tools > Inquiry > Area.
On the command line, type a (add).
Using one of the following methods, identify the first area:
Specify points defining a polygon, and then press Enter.
Type e (entity), select the entities you want to add, and then press Enter to complete the calculations.
On the command line, type s (subtract).
Using one of the following methods, identify the area to be subtracted:
Specify points defining a polygon, and then press Enter.
Type e (entity), select the entities you want to subtract, and then press Enter to complete the calculations.
To complete the command, press Enter.
Inquiry toolbar
Command line AREA
To calculate the area of the gasket using the Area command, first add the area of the entire gasket (A), and then subtract the areas of the two circles (B and C) 
As you select objects, the program displays the calculations. If the command bar is displayed, the information appears there. If the command bar is not displayed, the program opens the Prompt History window and displays the calculations.
Commands Reference
DIST: Measures the distance and angle between two points
ID: Displays the coordinate of a location
AREA: Calculates the area and perimeter of objects or of defined areas
LIST: Displays database information for selected objects
MASSPROP: Calculates the mass properties of regions or 3D solids
PROPERTIES: Controls properties of existing objects
UNITS: Controls coordinate and angle display formats and precision
CAL: Evaluates mathematical and geometric expressions
System Variables Reference
DISTANCE: Sets the display size for point objects
AREA: Stores the last area computed by the AREA command
PERIMETER: Stores the last perimeter value computed by the AREA or LIST commands