Modifying Commands (part 2)

3.3 Scaling the Object

Resize or Reshape an object

You can resize an object to make it longer/shorter in only one direction or to make it proportionally larger/ smaller. Also, you can stretch certain objects by moving vertex, endpoint or control point.

Lengthen objects

With LENGTHEN command, you can change the included angle of specified arcs & length of the objects like lines, open polylines, arcs, open splines and elliptical arcs.

The results are similar to extending & trimming. You can

1. Drag the object endpoint dynamically
2. Specify a new length/angle as a percentage of the total length/angle
3. Specify an incremental length/angle measured from an endpoint
4. Introduce the object's total absolute length/included angle

Stretch Objects:

With 'STRETCH' command, you can relocate the endpoints of objects that lie across/within a crossing selection window. The objects that you partially enclose by a crossing window are stretched and the objects that you completely enclose or that you select individually are moved rather than stretched.

If you want to stretch an object, then you must specify a base point & a point of displacement.

If you want to stretch the object with precision use grid snaps, object snaps, & relative co-ordinate entry.

Scaling objects:

Using 'SCALE' command you can resize an object or group of objects to make them proportionally larger/smaller. Scaling can be completed by picking a 2nd point or, by entering a scale factor at the keyboard. Sometimes, it is difficult to control the scaling precisely.

Any of the following method can be used to scale the objects.

1. Choose Modify (from menu bar), Scale

or

2. Click on the Scale icon (from toolbar)

or

3. Type SCALE (in the command prompt)

command: SCALE

4. Select the required object
5. Pick a pivot point to scale about base point: (point)
6. Type rotation angle <scale factor>/ reference: (point)

or

7. Pick a scale factor <scale factor>/ reference: (point)

scale factor: (points)

For instance:

\

If you are to scale the objects precisely, the best way is to enter a scale factor using the keyboard. Remember that the position of a new sized object is determined by the location of the base point. In the above figure, I have picked the midpoint of the base line of the object as a base point.

3.4 Creating Chamfer & Fillet

Chamfer:

A chamfer helps to connect any 2 objects with an angled line. In other words, this command makes you able to create a chamfer between any 2 non parallel lines as shown in the figure below. We can chamfer the objects like lines , xlines, polylines, rays and so on.

Chamfering can be done by:

1. Type CHAMFER (at the command prompt)

command: CHAMFER

2. Type in what way you want to chamfer the object (i.e. by distance or angle or something else)

Select first line or (polyline/ undo/distance /trim/angle /method/multiple): (choose any one, say, distance)

3. Type the chamfer distance

Specify first chamfer distance: (distance) (ENTER)

4. Type the next chamfer distance

Specify second chamfer distance: (distance) (ENTER)

For instance:

As you can see in the command sequence, there are a no. of options which you can use to control the way how chamfer command behaves.

Options:

Polyline: It chamfers all the vertices of a polyline simultaneously.

Distance: It allows us to specify the 2 chamfer distances.

Angle: It allows the angle between the 1st line & the chamfer to be specified.

Trim: It is used to control whether the original lines are trimmed to the chamfer or remain as they are.

Method: Used to toggle commands between distance & angle mode.

Fillet:

Fillet is a very useful command tool which is used to join any two objects by an arc or a small curved line. First you should use the 'FILLET' command to set the required radius 'r' & then a second time to select the 2 lines.

Fillet can be done by:

1. Type FILLET (in the command line)

Command: FILLET

2. Type radius or r

Select first object or [Polyline/ Undo/Radius/Trim/Multiple]: (1st fillet radius should be provided)

3. Hit the 'ENTER' key
4. Pick the first object to fillet with pick box.

Select first object or [Polyline/ Undo/Radius/Trim/Multiple]: (pick the 1st object)

5. Pick the second object to fillet

Select second object to apply corner: (pick the next object adjacent to 1st one)

3.5 Trimming & Extending of the Object

Trim:

This 'TRIM' command is used toremove the unwanted parts of the drawing objects. To trim an object you need to draw a second object that forms the 'cutting edge'. We can use lines, rays, circles, rays, xlines or ellipses as cutting edges. But, we cannot use Blocks & text as cutting edges. The illustration in the following drawing objects show s the result of 'TRIM' command.

It can be done as follows:

1. Type TRIM( in the command line)

Command: TRIM

2. Pick the cutting edge

Select object or <select all>: (pick cutting edge

3. Pick the part to be trimmed off

Select object to trim or shift-select to extend or

(Crossing/ Fence/Project /eRase/Edge /Undo): (pick the trimming part)

4. Press ENTER

The 'TRIM' command is a bit more complicated than the other modifying commands. In order to understand this command better about its working method, you need to follow the above command sequence and practice it. Remember that at each step of trimming you are given option to undo 'U' the previous trim. It can be very worth and useful if you unintentionally pick the wrong object.

Extend:

This 'EXTEND' command is useful to extend a line, but there must be a specified limit up to where it is to be extended i.e. another object should be included as a boundary line just before the line which is being extended as a barrier. Generally, only the lines are suitable to be extended and it is done by:

1. Type EXTEND (in the command line)

Command: EXTEND

2. Pick the boundary edge to extend to

Select objects: (select boundary object)

3. Press ENTER
4. Pick the objects to be extended

Select object to extend or shift-select to trim or

[Crossing/ Fence/Project/Edge/Undo]: (select objects)

Before :

After:

3.6 Breaking & Dividing

Break:

You can break an object into two objects with or without a gap between them. You can use the 'BREAK' command with lines, circles, polylines, ellipses, xlines, rays and so on. When you break a drawing object, either you need to select the object using the 1st break point & then pick the 2nd break point, or you can select the object & then pick the 2 break points.

You can create breaks in most geometric objects except:

1. Blocks
2. Dimensions
3. Mines
4. Regions

You can break objects by:

1. Type BREAK (in the command line)

Command: BREAK

2. Pick the object to break

Select object: (breaking object)

3. Type 'f' or 'first' if you want to break into two points. It breaks and then removes the part in between the selected two points.

Specify second break point or [First point]: f

4. Select a first breaking point

Select first break point: (select a point)

5. Select the second breaking point

Specify second break point: (select another point) (if you want to break the object only into two parts then select the second point above the first point)

In the above illustration figure, the middle part of one of the side of a rectangle has been removed.

Divide:

You can divide a selected object into a specified number of equal lengths as per your desire.

The object can be divided by:

1. Type DIVIDE (at the command prompt)

Command: DIVIDE

2. Pick object to divide

Select object to divide: (pick object)

3. Press ENTER
4. Type number of segments to divide the object

Enter the number of segments or [Block]: (number)

5. Press ENTER

Now, the object is divided into specified equal segments. Here, the dividing points might not appear on the drawing screen. For this you need to change the point size and you can also change the point type.

Note:

Ddptype: to change the point type and its size