2004

Extract or Calculate Geometric Information from Objects | 257
Example: Subtraction of Areas from a Calculation
In the following example, the closed polyline represents a metal plate with
two large holes. You first calculate the area of the polyline and then subtract
each hole. AutoCAD displays area and perimeter or circumference of each
object and a running total after each step.
Here is the command line sequence:
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.
See Also
“Create and Combine Areas (Regions)” on page 292
“Overview of Object Properties” on page 170
To calculate an area you define
1 From the Tools menu, choose Inquiry. Then choose Area.
2 Specify points in a sequence that defines the perimeter of the area to be
measured. Then press
ENTER.
AutoCAD connects the first and last points to form a closed area and
displays the area and perimeter measurements using the settings specified
with
UNITS.
Inquiry toolbar
1
2
total
area
3