STRECHING AND SCALING

Transcription

1 MODULE 25 STRECHING AND SCALING LEARNING OUTCOME After the completion of this module, you will be able to: Utilize the STRETCH and SCALE commands to change the size of objects and to enhance drawing productivity. Resizing Objects With Stretch command, you can resize objects to make them longer or shorter in only one direction or to make them larger or smaller. With the Scale command, you can make an object uniformly larger or smaller. A scale factor greater than 1 enlarges the original object. A scale factor between 0 and 1 makes it smaller. Selecting Objects There are many ways to select objects in AutoCAD. When using the stretching command we must use the crossing-window or the crossing-polygon option. The following table summarizes three different methods we use to select object. DIRECTION CALLED DISPLAY EFFECT Right to left Crossing - window Green box (with dotted outline) Selects any object that is either crossing the boundary or is inside it. Left to right Window selection Blue box Selects only objects that are completely within the box. Any direction Crossing - Polygon Green polygon (with dotted outline) Selects any object that is either crossing the boundary or is inside it

2 Using the Stretch command Institute of Applied Technology The Stretch command is used to stretch or move an object. Command Keyboard input / Alias Icon Menu Stretch Stretch / s Modify > Stretch Exercise1: Draw the square shown below and stretch it so it matches the figure labeled after stretching. Command: Stretch Select objects to stretch by crossing-window or crossing-polygon... Specify opposite corner: 1 found (Use the crossing-window method to select the objects) Specify base point or [Displacement] <Displacement>: endp of (Select the end point as shown) Specify second point or <use first point as (This will be the result)

3 Now, Stretch the resulted rectangle up 5 units. Command: Stretch Select objects to stretch by crossing-window or crossing-polygon... Specify opposite corner: 1 found (Use the crossing-window method to select the objects) Specify base point or [Displacement] <Displacement>: endp of (Select the end point as shown) Specify second point or <use first point as You can us the STRETCH command to move objects. Exercise 2: Draw an object similar to the one labeled before stretching and use the stretch command to make it similar to the one labeled after stretching. Command: Stretch Select objects to stretch by crossing-window or crossing-polygon... Specify opposite corner: 1 found (Use the crossing-window method to select the objects) Specify base point or [Displacement] <Displacement>: qua of (Select the quadrant of the circle as shown) Specify second point or <use first point as displacement>: end of P2 P2-87 -

4 Exercise 3: Draw an object similar to the one labeled before stretching and use the stretch command to make it similar to the one labeled after stretching. Command: Stretch Select objects to stretch by crossing-window or crossing-polygon... cp (Use the crossing-polygon method to select the objects) P6 First polygon point: Specify endpoint of line or [Undo]: Specify endpoint of line or [Undo]:P2 Specify endpoint of line or [Undo]:P3 Specify endpoint of line or [Undo]:P4 Specify endpoint of line or [Undo]:P5 Specify endpoint of line or [Undo]:P6 7 found Specify base point or [Displacement] <Displacement>: endp of P7 Specify second point or <use first point as displacement>: endp of P8 P3 P4 P7 P5 P2 P8-88 -

5 Drawing scale factor Drawing scale factor is a single number that represents a multiplier, such as 0.5 or 20. The drawing scale factor for a drawing is the conversion factor between a measurement in a CAD drawing and the real world. Using the Scale Command The scale command is used to enlarge or reduce selected objects proportionally in the X, Y, and Z directions. Command Keyboard input / Alias Icon Menu Scale Scale / sc Modify > Scale

6 Exercise 4: Draw the following object and scale it down using a scaling factor of 0.5. Command: Scale (Use the any method to select the objects) Specify base point: endp of Specify scale factor or [Copy/Reference] <0.7000>: 0.5 Tip If you want to keep the original object, use the copy option within the Scale command. Exercise 5: Draw an object similar to the one labeled before scaling and use the scale command to make it similar to the one labeled after scaling. Before Scaling After Scaling

7 Command: Scale Specify opposite corner: 6 found (You can use the window-selection to select the objects) Specify base point: endp of Specify scale factor or [Copy/Reference] <2.0000>: r (Type r for reference) Specify reference length < >: endp of P2 P2 Specify second point: endp of P3 P3 P4 Specify new length or [Points] < >: endp of P4 The result you will get is as follows:

8 Task Details Drawing Specifications Name Template Units Text Style Font AutoCAD 2D Exe- 25 IAT Module Template A3 Millimeters N/A N/A Layering Scheme Objects on Layer Name Color Linetype Lineweight Construction Objects Construction Green Continuous N/A All Objects Object Black/White Continuous N/A Centerlines Center Blue Center N/A Instructions: 1. Open IAT Module Template A3. 2. Scale all objects in the template using a scale factor of 2. Your base point is the lower left corner of the drawing frame. 3. Setup the layers as per the layering scheme. 4. Draw the object shown below. Your starting point is 230,450. Start point 230,

9 5. Copy the object to a new location as shown below. Change the object to match the dimensions shown below. Utilize the Stretch command. 295, Copy the original object to new locations as shown below and scale the one in the middle to fill in the space between the upper and lower one. 600, , ,

10 Module 25 Review Questions 1. The command that is used to enlarge or reduce selected objects proportionally in the X, Y, and Z directions is the command. a. scale b. stretch c. edit d. array 2. The alias used to start the Stretch command is. a. S b. St c. Sc d. Sca 3. The alias used to start the Scale command is. a. S b. St c. Sc d. Sca 4. The scale factor used to scale the shown object is: a. 1.5 b. 2 c. 0.5 d Which of the following selecting object methods is used with the stretch command? a. Crossing-window b. Window Selection c. Fence d. Box

11 6. The minimum number of points used to define a polygon when using the crossing-polygon selection method is. a. 1 b. 2 c. 3 d The crossing-window method is used to select objects. How many objects will be selected in the object shown? a. 6 b. 8 c. 10 d When using the window selection, the box created from. a. left to right b. right to left c. up to down d. any direction 9. The best way to select the shaded object is the. a. individual object selection b. crossing window c. crossing polygon d. window-selection 10. Which of the following is the Scale command icon? a. b. c. d