AREA

To calculate an area you define

1. Click Tools menu INCLUDEPICTURE "ms-its:C:\\Program%20Files\\AutoCAD%202006\\help\\acad_aug.chm::/ac.menuaro.gif" \* MERGEFORMATINET

InquiryArea.

2. Specify points in a sequence that defines the perimeter of the area to be measured. Then press ENTER.

The first and last points are connected to form a closed area and the area and perimeter measurements are displayed using the settings specified with UNITS.

Inquiry toolbar Command line:AREA

You can obtain the area and perimeter defined by selected objects or a sequence of points. You can calculate and display the area and perimeter of a sequence of points or of any of several types of objects. If you need to calculate the combined area of more than one object, 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.

Calculate a Defined 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 displayed information differs according to the type of object you select:

Circles. Area and circumference are displayed.

Ellipses, closed polylines, polygons, planar closed spline curves, and regions. Area and perimeter are displayed. 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 are displayed. The area is computed as though a straight line connected the start point and endpoint.

AutoCAD 3D solids. Total 3D area for the object is displayed.

Example: How Various Areas Are Calculated

Calculate Combined Areas

You can measure more than one area, either 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 one or more areas from a combined area that you have already calculated. In the example, the area of the floor plan is first calculated, and then a room is subtracted.

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. Area and perimeter or circumference of each object are displayed, with 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:PressENTER

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:PressENTER

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

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.

STRETCH

Moves or stretches objects

Modify toolbar:

Modify menu: Stretch

Command line:stretch

Select objects to stretch by crossing-window or crossing-polygon.. ( selection left to right to stretch else selection right to left will move)Select objects: Use the cpolygon option or the crossing object selection method, and press ENTER. Individually selected objects and objects that are completely enclosed by the crossing selection are moved rather than stretched.

STRETCH does not modify 3D solids, polyline width, tangent, or curve-fitting information.

Base Point

Specify base point or [Displacement] : Specify a base point or enter displacement coordinates

Specify second point or : Specify a second point, or pressENTER to use the previous coordinates as a displacement

Displacement

Specify displacement : Enter displacement values for X,Y (and optionally Z)

If you enter a second point, the objects are stretched the vector distance from the base point to the second point. If you press ENTER at the Specify Second Point of Displacement prompt, the first point is treated as an X,Y,Z displacement.

Objects that are partially enclosed by a crossing window are stretched.

Objects that are completely enclosed within the crossing window, or that are selected individually, are moved rather than stretched.

SCALEEnlarges or reduces selected objects proportionally in the X, Y, and Z directions

Modify toolbar:Modify menu: Scale

Shortcut menu:Select the objects to scale, and right-click in the drawing area. Click Scale.

Command line:scale Select objects: Use an object selection method and press ENTER when you finish

Specify base point: Specify a point The base point you specify identifies the point that remains in the same location as the selected objects change size (and thus move away from the stationary base point).

Specify scale factor or [Copy/Reference]: Specify a scale, enterc, or enter rTo scale an object by a scale factor1. Click Modify menu Scale.

2. Select the object to scale.

3. Specify the base point.

4. Enter the scale factor or drag and click to specify a new scale. A scale factor greater than 1 enlarges the object. A scale factor between 0 and 1 shrinks the object.

Scaling changes the size of all dimensions of the selected object. A scale factor greater than 1 enlarges the object. A scale factor less than 1 shrinks the object.

Scale Objects Using a Reference DistanceYou can also scale by reference. Scaling by reference uses an existing distance as a basis for the new size. To scale by reference, specify the current distance and then the new desired size. For example, if one side of an object is 4.8 units long and you want to expand it to 7.5 units, use 4.8 as the reference length.

You can use the Reference option to scale an entire drawing. For example, use this option when the original drawing units need to be changed. Select all objects in the drawing. Then use Reference to select two points and specify the intended distance. All the objects in the drawing are scaled accordingly.

LENGTHENChanges the length of objects and the included angle of arcs

Modify menu: Lengthen

Command line:lengthen Select an object or [DElta/Percent/Total/DYnamic]: Select one object or enter an option With LENGTHEN, you can change the included angle of arcs and the length of the following objects:

Lines

Arcs

Open polylines

Elliptical arcs

Open splines. The results are similar to extending and trimming. You can

Drag an object endpoint dynamically

Specify a new length or angle as a percentage of the total length or angle

Specify an incremental length or angle measured from an endpoint

Specify the object's total absolute length or included angle To change the length of an object by dragging

1. Click Modify menuLengthen.

2. Enter dy (Dynamic Dragging mode).

3. Select the object you want to lengthen.

4. Drag the endpoint closest to the point of selection, and specify a new endpoint.

The selected object is lengthened or shortened without changing its location or orientation.

DONUTTo create a donut

1. Click Draw menu Donut.

2. Specify the inside diameter (1).

3. Specify the outside diameter (2).

4. Specify the center of the donut (3).

5. Specify the center point for another donut, or press ENTER to complete the command.

Draws filled circles and ringsDraw menu: Donut

Command line:donut

Specify inside diameter of donut : Specify a distance or press ENTER

If you specify an inside diameter of 0, the donut is a filled circle.

Specify outside diameter of donut : Specify a distance or press ENTER

Specify center of donut or : Specify a point (1) or press ENTER to end the command

How the interior of a donut is filled depends on the current setting of the FILL command.DISTANCEMeasures the distance and angle between two points

Inquiry toolbar:Tools menu: Inquiry Distance

Command line:dist (or 'dist for transparent use)

Specify first point: Specify a point

Specify second point: Specify a point

Distance = calculated distance, Angle in XY plane = angle,

Angle from XY plane = angle

Delta X = change in X, Delta Y = change in Y, Delta Z = change in Z

The true 3D distance between points is reported. The angle in the XY plane is relative to the current X axis. The angle from the XY plane is relative to the current XY plane. DIST assumes the current elevation for the first or second point if you omit the Z coordinate value.The distance is displayed using the current units format.

To determine the relation between two points, you can display the

Distance between them

Angle between the points in the XY plane

Angle of the points from the XY plane

Delta, or changed, X, Y, and Z distances between them

The ID command lists the X, Y, and Z coordinate values of a specified point

DIVIDEPlaces evenly spaced point objects or blocks along the length or perimeter of an object

Draw menu: Point (Divide

Command line:divide Select object to divide: Use an object selection method Enter number of segments or [Block]: Enter a value from 2 through 32,767, or enter bYou can divide a selected object into a specified number of equal lengths.

You can create points or insert blocks on an object at a specific number of equal intervals. This operation does not actually break an object into individual objects; it only identifies the location of the divisions so that you can use them as geometric reference points.

The starting point for measurements or divisions varies with the object type. For lines or open polylines, the starting point is the endpoint closest to the selection point. For closed polylines, it is the polyline start point. For circles, it is at the angle from the center point that is equivalent to the current snap angle. For example, if the snap angle is 0, the circle starts at the three o'clock position and continues counterclockwise. If the point marker is displayed as a single dot (the default setting), you may not be able to see the segments. You can change the style of the point markers using several methods. To change the point style in a dialog box, you can use DDPTYPE, or choose Point Style from the Format menu. The PDMODE system variable also controls the appearance of point markers. For example, you can change the value to make points appear as crosses. PDSIZE controls the size of point objects.

To insert points to mark equal segments1. Click Draw menu Point Divide.

2. Select a line, circle, ellipse, polyline, arc, or spline.

3. Enter the number of segments you want.

A point is placed between each segment. To insert blocks to mark equal segments on an object

1. If necessary, create the block you want to insert.

2. Click Draw menu Point Divide.

3. Select a line, arc, circle, ellipse, polyline, or spline.

4. Enter b (Block).

5. Enter the name of the block you want to insert.

6. Enter y to align the blocks with the divided object. Enter n to use a rotation angle of 0 degrees.

7. Enter the number of segments you want.

BREAKTo break an object

1. Click Modify menuBreak.

2. Select the object to break.

By default, the point at which you select the object is the first break point. To select a different pair of break points, enter f (First) and specify the first break point.

3. Specify the second break point.

To break an object without creating a gap, enter @0,0 to specify the previous point.

Modify toolbarCommand line:BREAK

The portion of the object is erased between the two points that you specify. If the second point is not on the object, the nearest point on the object is selected; therefore, to break off one end of a line, arc, or polyline, specify the second point beyond the end to be removed.To split an object in two without erasing a portion, enter the same point for both the first and second points. You can do this by entering @ to specify the second point.

Lines, arcs, circles, polylines, ellipses, splines, donuts, and several other object types can be split into two objects or have one end removed.

The program converts a circle to an arc by removing a piece of the circle starting counterclockwise from the first to the second point.

You can break an object into two objects with or without a gap between them. You can also join objects to make a single object.

Use BREAK to create a gap in an object, resulting in two objects with a gap between them. BREAK is often used to create space for block or text.

You can create breaks in most geometric objects except

Blocks

Dimensions

Mlines

Regions

JOINTo join objects

1. Click Modify menuJoin.

2. Select the source object to which you want to join objects.

3. Select one or more objects to join to the source object.

Valid objects include arcs, elliptical arcs, lines, polylines, and splines. Additional restrictions for each type of objects are described in the JOIN command.

Joins objects to form a single, unbroken object

Modify toolbar:Modify menu: Join

Command line:join

Select source object: Select a line, polyline, arc, elliptical arc, or spline

Depending on the source object selected, one of the following prompts is displayed:

Line

Select lines to join to source: Select one or more lines and press ENTER

The line objects must be collinear (lying on the same infinite line), but can have gaps between them.Polyline

Select objects to join to source: Select one or more objects and press ENTER

The objects can be lines, polylines, or arcs. The objects cannot have gaps between them, and must lie on the same plane parallel to the UCS XY plane.Arc

Select arcs to join to source or [cLose]: Select one or more arcs and press ENTER, or enter L

The arc objects must lie on the same imaginary circle, but can have gaps between them. The Close option converts the source arc into a circle.

NoteWhen joining two or more arcs, the arcs are joined counterclockwise beginning from the source object.Elliptical Arc

Select elliptical arcs to join to source or [cLose]: Select one or more elliptical arcs and press ENTER, or enter L

The elliptical arcs must lie on the same ellipse, but can have gaps between them. The Close option closes the source ellipstical arc into a complete ellipse.

NoteWhen joining two or more elliptical arcs, the elliptical arcs are joined counterclockwise beginning from the source object.Spline

Select splines to join to source: Select one or more splines and press ENTER

The spline objects must lie in the same plane, and must be contiguous (lying end-to-end).

XLINE or Construction LineCreates an infinite line

Draw toolbar:Draw menu: Construction Line

Command line:xline

Specify a point or [Hor/Ver/Ang/Bisect/Offset]: Specify a point or enter an option

To create a construction line by specifying two points (in both directions)1. Click Draw menu Construction Line.

2. Specify a point to define the root of the construction line.

3. Specify a second point through which the construction line should pass.

4. Continue to specify construction lines as needed.

All subsequent xlines pass through the first point specified.

5. Press ENTER to end the command.Lines that extend to infinity in one or both directions, known as rays and construction lines, respectively, can be used as references for creating other objects. For example, you can use construction lines to find the center of a triangle, prepare multiple views of the same item, or create temporary intersections to use for object snaps.

Infinite lines do not change the total area of the drawing. Therefore, their infinite dimensions have no effect on zooming or viewpoints, and they are ignored by commands that display the drawing extents. You can move, rotate, and copy infinite lines just as you can move, rotate, and copy other objects. You may want to create infinite lines on a construction line layer that can be frozen or turned off before plotting.

A construction line (xline) can be placed anywhere in three-dimensional space. You can specify its orientation in several ways. The default method for creating the line is the two-point method: you specify two points to define the orientation. The first point, the root, is the conceptual midpoint of the construction line, that is, the point snapped to by the Midpoint object snap.

You can also create construction lines in several other ways.

Horizontal and Vertical. Create construction lines that pass through a point you specify and are parallel to the X or Y axis of the current UCS.

Angle. Creates a construction line in one of two ways. Either you select a reference line and then specify the angle of the construction line from that line, or you create a construction line at a specific angle to the horizontal axis by specifying an angle and then a point through which the construction line should pass.

Bisector. Creates a construction line that bisects an angle you specify. You specify the vertex and the lines that create the angle.

Offset. Creates a construction line parallel to a baseline you specify. You specify the offset distance, select the baseline, and then indicate on which side of the baseline to locate the construction line.

Rays

A ray is a line in three-dimensional space that starts at a point you specify and extends to infinity. Unlike construction lines, which extend in two directions, rays extend in only one direction. Using rays instead of construction lines can help reduce visual clutter. Like construction lines, rays are ignored by commands that display the drawing extents.

To create a ray ( in one direction only)1. Click Draw menu Ray.

2. Specify a starting point for the ray.

3. Specify a point through which the ray should pass.

4. Continue to specify points to create additional rays as needed.

All subsequent rays pass through the first point specified.

5. Press ENTER to end the command.