ىلولاا ةلحرملا · Ameer Mosa Thoeny. 2 1-POLYGON: The POLYGON command enables you to...

1

Department of Computer Engineering& Information Technology

قسم هندسه الحاسبات و تكنلوجيا المعلومات

المرحلة االولى

Lecture (13)

Polygon, Polyline and donut

Issued by Assistant Lecturer

Ameer Mosa Thoeny

2

1-POLYGON:

The POLYGON command enables you to draw multi-sided,

closed figures with equal side lengths. You can draw polygons that

have from 3 to 1,024 sides. To draw a polygon, choose Polygon from

the Draw toolbar.

First specify the number of sides. Then choose one of three methods

of defining the polygon.

There are three ways to draw polygon

1. Edge option: Choose the Edge option. Specify the two endpoints of any edge of

the polygon to complete the polygon.

The command syntax for copy is as follows:

Command: polygon

Enter number of sides <5>: 5

Specify center of polygon or [Edge]: e

Specify first endpoint of edge: 10,10

Specify second endpoint of edge: 20,20

2. Inscribed in circle: After specifying the center, choose Inscribed in Circle. Then

specify the radius from the center to a vertex (point). This defines the

polygon with reference to an imaginary circle whose circumference

touches all the vertices of the polygon.

3


Command: polygon


Specify center of polygon or [Edge]: 20,20

Enter an option [Inscribed in circle/Circumscribed about circle] <I>:I

Specify radius of circle: 10

3. Circumscribed about circle:

After specifying the center, choose Circumscribed about Circle.

Then specify the radius from the center to the midpoint of a side. This

defines the polygon with reference to an imaginary circle whose

circumference touches all the midpoints of the polygon’s sides.


Command: polygon


Specify center of polygon or [Edge]: 20,20

Enter an option [Inscribed in circle/Circumscribed about circle] <I>: c

Specify radius of circle: 10

4

2-PLOLYLINE:

The command syntax for copy is as follows: Command: pline

Specify start point: 0,0

Current line-width is 2.0000

Specify next point or [Arc/Halfwidth/Length/Undo/Width]: w

Specify starting width <2.0000>: 2

Specify ending width <2.0000>: 2

Specify next point or [Arc/Halfwidth/Length/Undo/Width]: 20,20

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: 40,0




Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:enter

Command: pline








Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

5

Command: pline







Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: w




Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

3-Making Donuts A donut is a wide polyline that looks like two concentric circles. You

define a diameter for the inner and outer circles.

Donuts are often used in electrical drawings to create symbols. If the inner

circle’s radius is zero, you create a filled-in circle.

6

The real view of donut as below:


Command: donut

Specify inside diameter of donut <1.0000>: 20

Specify outside diameter of donut <5.0000>: 80

Specify center of donut or <exit>: 10,10

Specify center of donut or <exit>:

7




Lecture (14) Create Region and

Boolean command: Union Subtract Intersect


Ameer Mosa Thoeny

8

1) REGION: Regions are two-dimensional surfaces.

The region command converts one object or a set of objects forming

a closed shape into one object called a Region.

This similar to the way in which a set of objects (lines, arcs, plines, etc.)

forming a closed shape and having matching and points can be converted

into a closed pline.

A region, however, has special properties:

1. Several regions can be combined with Boolean operations known as

union, subtract, and intersect to form a ―composite‖ region.

2. A region is considered a planer surface. Region can be used with

surface modeling.

The appearance of the object does not change after the conversion,

even though the resulting shape is one object.

Although the region appears to be no different than a closed pline, it is

more powerful because several regions can be combined to form complex

shapes (composite regions) using the three Boolean operations.

And our drawing can calculate more information from regions than from

polylines, such as the centroid, moments of inertia, and other properties

relating to mass. You can also create complex shapes by combining,

subtracting, and intersecting regions.

Although these commands are most often used for 3D drawing, they’re often

used in 2D drawing as a preparation for 3D drawing.

Consider the shape below composed of four connecting lines, using region

combines the shape into one object, a region.

To create a region, choose Region from the Draw toolbar. The prompt

asks you to select objects. Select all of the objects and press Enter to end

object selection.

9

Our can be creating using region command as shown below:

Command: region

Select objects: pick L1




Select objects: enter

1 region created.

2) Boolean commands: The Boolean operators, union, subtract, intersect, can be used within

regions as well as solids. Any number of these commands can be used with

regions to form complex geometry.

The first step is to convert the lines and circle to region, then union, subtract,

intersect can be used.

a. Union: Union combines two or more regions (or solids) into one region or

(solids). Invoking union causes AutoCAD to prompt you to select objects.

You can only existing regions (or solids).

We can use it as shown below:

Command: union

Select objects: pick (region)

Select objects: pick (region)


The selected regions are combined into one composite region.

Before union

After union

10

b. Subtract: Subtract enables you to remove on region (or set of regions) from

another. The regions must be created before using subtract (or another

Boolean operator). Subtract also works with solids (as do the other Boolean

operations).

There are two steps to subtract:

1) Select the region or set of regions to ―subtract from‖ (these that you

with to keep).

2) Select the region ―to subtract‖ (these you want to remove).


Command: subtract

Select objects: pick


Select regions to subtract



Before union

After union

11

c. Intersect: Intersect is the Boolean operator that finds the common area from

two or more regions.


Command: intersect




Before union

After union

12

Exercise:

Create the drawing below using (rectangular and circle) drawing command

Then use region and Boolean command to modify it?

13




Lecture (15) Dimensions

Linear, Aligned, diameter, radius, Angular and

Style Manager


Ameer Mosa Thoeny

14

Working with Dimensions: Dimensioning is usually done after you complete all or most of a drawing.

When you dimension a drawing all at once, you can create a unified,

organized look for your dimensions.

The elements of a dimension: A dimension is a complex object, containing many parts. Understanding

these parts and how they relate to the object you’re dimensioning is an

important first step. Figure below shows a typical linear dimension.

✦Extension lines: These extend from the dimensioned object to the

dimension line and arrowheads.

✦Dimension text: This tells you the actual measurement of the

dimensioned object. You can format this text in decimals, fractions,

scientific units, and so on.

✦Dimension line: This extends between the extension lines.

✦ Arrowheads: These mark the intersection of the dimension line and the

extension lines. They can take several forms, such as tick marks, open

arrows, or dots.

15

1) Linear Dimensions Just as the most common objects are lines, the most common

dimensions are linear dimensions. Use linear dimensions for lines, a straight

segment of a polyline, or a straight segment in a block. You can also use a

linear dimension for arcs and circles — you get the linear length of the arc

(not its perimeter length) and the diameter of the circle.

Specifying the linear dimensioned object To dimension a line, choose Linear Dimension from the Dimension toolbar

or from standard bar- dimensions – linear.

Command: dimlinear

Specify first extension line origin or <select object>: pick

Specify second extension line origin: pick

Specify dimension line location or [Mtext/Text/Angle/Horizontal/Vertical/Rotated]: pick

Dimension text = 24.7411

2) Aligned Dimensions

When you want to dimension a linear object that is not orthogonal, use an

aligned dimension. The dimension lines of an aligned dimension are always

parallel to the object, unlike rotated dimensions. An aligned dimension

measures the actual length of the object, not a vertical or horizontal distance

that you dimension with a linear dimension.

16

Specifying the Aligned dimensioned object To dimension a non orthogonal line, choose Aligned Dimension from the

Dimension toolbar or from standard bar- dimensions – Aligned.

Command: dimaligned

Specify first extension line origin or <select object>: pick

Specify second extension line origin: pick

Specify dimension line location or[Mtext/Text/Angle]: pick

Dimension text = 21

Dimensioning Arcs and Circles 3) diameter dimensions When you want to dimension of an arc or circle objects, use an diameter

dimension.

Specifying the circle diameter dimension To dimension a circle diameter, choose diameter Dimension from the

Dimension toolbar or from standard bar- dimensions – diameter.

Command: dimdiameter

Select arc or circle: pick

Dimension text = 8

17

4) Radius dimensions

When you want to dimension of an arc or circle objects, use a radius

dimension.

Specifying the circle radius dimension To dimension a circle radius, choose radius Dimension from the

Dimension toolbar or from standard bar- dimensions – radius.

Command: dimradius


Dimension text = 4

5) Marking arc and circle centers Circle and arc centers are often marked in mechanical drawings because the

center is an important aspect of a circle or arc but is not obvious without a

mark. You set the size and type of mark when you create a dimension style.

Specifying the Center Mark dimensioned object To dimension a center mark, choose center Mark Dimension from the

Dimension toolbar or from standard bar- dimensions – center Mark.

Command: dimcenter


18

6) Angular dimensions

When you want to dimension of an arc or angle objects, use an angular

dimension.

Specifying the Angular dimension To dimension a angel or arc, choose angular Dimension from the

Dimension toolbar or from standard bar- dimensions – angular.

Command: dimangular

Select arc, circle, line, or <specify vertex>: pick

Specify dimension arc line location or [Mtext/Text/Angle]: pick

Dimension text = 136

19

Understanding Dimension Styles

You should create your dimension styles before dimensioning. In

general, you create a dimension style, save it in your template drawings, and

(you hope) rarely have to deal with it again.

To create a dimension style, choose Dimension Style from the Dimension

toolbar to open the Dimension Style Manager, or from standard bar-

dimensions – style.

To create a new style, click New to open the Create New Dimension Style

dialog box.

20

Then specify the wanted parameters as below:

The New Dimension Style dialog box has the following tabs:

✦ Lines: Sets specifications for dimension lines and extension lines.

✦ Symbols and Arrows: Sets specifications for arrowheads, center marks,

the arc length symbol and the jog angle for dimensioning large radii.

✦ Text: Determines the appearance, placement, and alignment of

dimension text.

✦ Fit: Sets how text and arrows fit inside narrow dimensions, as well as

where text is placed when it doesn’t fit in its default position. This tab also

allows you to set the scale factor for dimension features, and whether to

place a dimension line inside narrow dimensions.

✦ Primary Units: Determines the format and precision for the primary

measuring unit for both linear and angular dimensions.

✦ Alternate Units: Determines the format and precision for secondary

units, if turned on (such as metric measurements if your primary units are

English, or vice versa).

✦ Tolerances: Formats tolerances.

21

NOTE:

a. Changing line type done from properties bar.

b. Change precision then, right click on dimension –precision -0

As shown below:

22




Lecture (16) Rotate and Explode


Ameer Mosa Thoeny

23

1. Rotating objects:

You can easily rotate an object or objects around a base point that you

specify. The base point is usually an object snap point on the object. To

indicate the rotation, specify an angle of rotation.

As explained before, zero degrees is generally to the right, and

degrees increase counterclockwise, although you can change this convention.

How to rotate object: 1. To rotate an object, choose Rotate from the Modify toolbar and select

an object. Alternatively, select an object and then choose Rotate from

the Modify toolbar.

2. By the prompt using command: Rotate

Methods use Rotate command: There are two ways to run rotate command as shown below:

1. Using normal rotate from 0 angles on right side and counterclockwise:

Command: rotate

Current positive angle in UCS: ANGDIR=counterclockwise ANGBASE=0



Specify base point: pick

Specify rotation angle or [Reference]: 90

Before rotate After rotate

24

2. Using reference option to determine new 0 angle according specify angle or two point:

Command: rotate

Current positive angle in UCS: ANGDIR=counterclockwise ANGBASE=0



Specify base point: pick

Specify rotation angle or [Reference]: r

Specify the reference angle <0>: Specify second point:

Specify the new angle: 90

Before rotate After rotate

2. Explode command: You can explode object into their original objects. You may

need to do this to edit it.

How to explode object: 1. To rotate an object, choose explode from the Modify toolbar and

select an object. Alternatively, select an object and then choose Rotate

from the Modify toolbar.

2. By the prompt using command: explode

Methods use explodes command: There are two ways to run rotate command as shown below:

Command: explode


25

Exercise1: use polygon command, explode and rotate to drawing the

following shape, where the circle radius of outer polygon is 10unit

and the circle radius of inner polygon is 4.5unit:

Exercise2: draw the following shape using suitable command:

ىلولاا ةلحرملا · Ameer Mosa Thoeny. 2 1-POLYGON: The POLYGON command enables you to...

Documents

Transcript of ىلولاا ةلحرملا · Ameer Mosa Thoeny. 2 1-POLYGON: The POLYGON command enables you to...