Autodesk 05720-017408-9621 - AE AUTOCAD LT 2000I LAB-PK 10U CD Скачать руководство пользователя страница 20 | Manualshive

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Autodesk 05720-017408-9621 - AE AUTOCAD LT 2000I LAB-PK 10U CD Скачать руководство пользователя страница 20

Geometric Construction Basics 1-19

Questions:

1.  What is the first thing we should consider when starting a new model?

2.  How do the GRID and SNAP options assist us in sketching?

3.  List and describe the different coordinate entry methods available in AutoCAD LT?

4.  List and describe two types of coordinate systems commonly used for planar

geometry.

5. Identify the following commands:

(a)

(b)

(c)

(d)

Tan, Tan, Radius

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Содержание 05720-017408-9621 - AE AUTOCAD LT 2000I LAB-PK 10U CD

Страница 1: ...WWW SDCACAD COM PUBLICATIONS Randy H Shih Jack Zecher ...

Страница 2: ...AutoCAD LT 2000 MultiMedia Tutorial 1 1 Lesson 1 Geometric Construction Basics ...

Страница 3: ...ting and modifying Straight lines and circles are used in almost all of the technical designs In examining the different types of planar geometric entities we can see that triangles and polygons are planar figures bounded by straight lines Ellipses and Splines can be constructed by connecting arcs with different radii As we gain some experience in creating lines and circles the similar procedures ...

Страница 4: ...The three numbers represent the location of the cursor in the X and Y directions We can treat the Graphics window as if it is a piece of paper and we are using the graphics cursor as if it is a pencil with which to draw 4 We will create a freehand sketch of a five point star using the LINE command Create the sketch near the center of the Drawing window Do not be overly concerned with the size or t...

Страница 5: ...s known as the interactive method where we use the cursor to specify locations on the screen This method is perhaps the fastest way to specify locations on the screen However it is rather difficult to try to create a line of a specific length by watching the displayed coordinates It would be helpful to know what one inch or one meter looks like on the screen while we are creating entities AutoCAD ...

Страница 6: ...inates display at the bottom of the screen The GRID option creates a pattern of dots that extends over an area on the screen Using the grid is similar to placing a sheet of grid paper under a drawing The grid helps you align objects and visualize the distance between them The grid is not displayed in the plotted drawing The default grid spacing which means the distance in between two dots on the s...

Страница 7: ...on the screen cursor and all input coordinates are snapped to the nearest point on the grid The default snap interval is 0 5 inches and aligned to the grid points on the screen 3 Click on the LINE icon in the Draw toolbar In the command prompt area the message _line Specify first point is displayed 4 Create another sketch of the star with the GRID and SNAP options switched on 5 Use the right mouse...

Страница 8: ...n so that we can more easily move the cursor on top of objects We can toggle the Status Bar options on and off in the middle of another command 3 Select any two lines on the screen and right mouse click once to accept the selections The selected two lines are erased Repeat the last command 1 Inside the Graphics window click once with the right mouse button to bring up the popup option menu 2 Pick ...

Страница 9: ... selected 5 Inside the Graphics window right mouse click to proceed with erasing the selected entities On your own create a sketch of your choice using the LINE command Experiment with using the different commands we have discussed so far such as switching the GRID and SNAP options on and off in the middle of a command Do not be in a hurry to rush through the tutorials Build up your CAD skills by ...

Страница 10: ...in the CAD system Information such as the coordinate values in world space for all endpoints center points etc along with the descriptions of the types of entities are all stored in the file Knowing that AutoCAD stores designs by keeping coordinate data helps us understand the inputs required to create entities The icon near the bottom left corner of the default AutoCAD Graphics Window shows the p...

Страница 11: ...e X axis Absolute and Relative Coordinates AutoCAD LT 2000 also allows us to use absolute and relative coordinates to quickly construct objects Absolute coordinate values are measured from the current coordinate system s origin point Relative coordinate values are specified in relation to previous coordinates The coordinate display area can also be used as a toggle switch each left mouse click wil...

Страница 12: ... point on the current coordinate system relative to the origin Relative rectangular coordinates Format X Y Type the X and Y coordinates relative to the last point Relative polar coordinates Format Distance angle Type a distance and angle relative to the last point Direct Distance Entry Technique Specify a second point by first moving the cursor to indicate direction and then entering a distance Th...

Страница 13: ...aper is taken care of by the CAD systems This allows the designers and CAD operators to concentrate their attentions on the more important issues the design 1 Select the LINE command icon in the Draw toolbar In the command prompt area near the bottom of the AutoCAD Graphics window the message _line Specify first point is displayed AutoCAD expects us to identify the starting location of a straight ...

Страница 14: ...n see the sketched line Notice the scroll bars can also be used to adjust viewing of the display 6 Press the Esc key to exit the PAN command Notice that AutoCAD goes back to the LINE command 7 We will create a vertical line by using the relative rectangular coordinates entry method relative to the last point we specified Specify next point or Close Undo 0 2 5 Enter 8 We can mix any of the entry me...

Страница 15: ...e measured relative to the reference point 12 Move the cursor directly to the left of the last point and use the direct distance entry technique by entering 6 5 Enter 13 For the last segment of the sketch we can use the CLOSE option to connect back to the starting point Inside the Graphics window right mouse click and a popup menu appears on the screen 14 Select Close with the left mouse button to...

Страница 16: ...n the pull down menus select Draw Circle Center Diameter Notice the different options available under the circle submenu Center Point Draws a circle based on a center point and a diameter or a radius 3 Points Draws a circle based on three points on the circumference 2 Points Draws a circle based on two endpoints of the diameter TTR Tangent Tangent Radius Draws a circle with a specified radius tang...

Страница 17: ... Specify center point for circle or 3P 2P Ttr tan tan radius 3 3 Enter 3 In the command prompt area the message Specify diameter of circle is displayed Specify diameter of circle 2 5 Enter 4 Inside the Graphics window right mouse click to bring up the popup option menu 5 Pick Repeat Center Diameter with the left mouse button in the popup menu to repeat the last command 6 Using the relative rectang...

Страница 18: ... Circle command in AutoCAD is to specify the Radius and the last radius used is also displayed in brackets Specify Diameter of circle 2 50 1 5 Enter Saving the CAD file 1 In the pull down menus select File Save As 2 In the Save Drawing As dialog box select the folder in which you want to store the CAD file and enter GuidePlate in the File name box ...

Страница 19: ...n the Save Drawing As dialog box to accept the selections and save the file Exit AutoCAD LT To exit AutoCAD LT 2000 select File then choose Exit from the pull down menu or type QUIT at the command prompt Select the folder to store the file Enter GuidePlate ...

Страница 20: ...ting a new model 2 How do the GRID and SNAP options assist us in sketching 3 List and describe the different coordinate entry methods available in AutoCAD LT 4 List and describe two types of coordinate systems commonly used for planar geometry 5 Identify the following commands a b c d Tan Tan Radius ...

Страница 21: ...1 20 AutoCAD LT 2000 MultiMedia Tutorial Exercises 1 2 ...

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