This semester we studied the course of AUTO CAD, and I really realized the practicability of this drawing system. At the same time, I think that in the process of mechanical design, drawings are the carrier of design ideas, and having good drawing ability is the most basic quality of every designer. Although the exam is over now, I feel that my learning process is not over yet, and there are still many places to improve.

Speaking of its usability, I believe many students feel the same way. We used to draw engineering drawings by hand, and it took two hours to draw a complete A3. I still remember that the final surveying and mapping took more than 20 hours, which made everyone feel tired. Moreover, attention should be paid to the neatness of drawings, the width of lines and the beauty of fonts, and the drawing process takes a lot of time. Now there is no problem in using AUTO CAD, and the thick and thin lines are standardized with "features", which is clear at a glance. The size is also quite accurate, as much as you entered on the command line, and you don't have to compare it with a T-square on the drawing. It's still not accurate in the end. When drawing lines and connecting lines, the advantages of CAD size are more obvious. For example, drawing a circle tangent to a straight line can only be done by feeling, and each drawing is different and asymmetrical in any way. With CAD drawing, you can catch the tangent point by opening object snap, which is fast and accurate! Dimension marking is even faster. You can complete the marking by dragging two points and clicking the left button. You don't need to draw arrows or mark words. As long as you design your own marking format, the computer can mark papers as required. Inserting text is also convenient. Entering text content in a multi-line text editor can produce absolutely standard national standard characters, which are much more beautiful than our handwritten characters! Roughness, datum symbol, title bar, etc. You can insert it at will without drawing one by one. It's really fast to use!

All the above are the advantages of drawing two-dimensional drawings with AUTO CAD. 2D drawing is not only convenient and fast, but also AUTO CAD, as the most powerful drawing tool in the world, is equally excellent in drawing 3D drawing! Open "isometric drawing" and press F5 to switch the drawing direction to draw isometric drawing. At the same time, its physical function can stretch the plane figure into a solid figure and chamfer it on the solid figure. So first draw a plan, convert the functions into three dimensions, then combine them, and then edit and calculate entities such as intersection, difference and union to get accurate and beautiful three-dimensional graphics. Moreover, when the model space is converted to the paper space, the top view and bottom view of three-dimensional graphics can be expressed, which is unified with the previous engineering drawings. The difference is that manual drawing always needs to draw three views, but here none is needed, just change the projection direction of three-dimensional graphics.

In short, if I have to use three words to express my feelings about AUTO CAD, it is fast, accurate and beautiful! Combined with your own situation, continue to practice using AUTOCAD, so that you can use it easily and make it an assistant for your future study and work. At the same time, it is necessary to cultivate good painting habits, maintain a rigorous attitude and use scientific learning methods in order to be comfortable!

CAD experience

The foundation is very important.

Practice has proved that the drawing ability of "manual sketchpad" is the basis of computer drawing ability. Learning AutoCAD requires a certain knowledge and ability of descriptive geometry and a certain drawing ability, especially geometric drawing ability. Generally speaking, students with good engineering drawing level in our class are easier to learn and get better grades!

Step by step

The whole learning process should adopt a step-by-step approach. First of all, we should understand the basic knowledge of computer drawing such as relative rectangular coordinates and relative polar coordinates, so as to master the application technology of AutoCAD 2000 from simple to complex.

Step 3 apply what you have learned

When learning AutoCAD 2000 commands, we should always combine practical application, and don't spend our main energy on learning each command in isolation. The principle of applying what you have learned should run through the whole learning process, so that you can have a profound and vivid understanding of drawing commands, which is conducive to cultivating your ability to complete drawing independently with AutoCAD 2000.

4. Practice makes perfect

As a computer experiment book, the matching Computer Drawing Problem Set can help us to understand and be familiar with the commands of AutoCAD 2000. We should force ourselves to make several comprehensive examples and draw the graphics in detail, so as to grasp the whole drawing process from a global perspective and strive to devote ourselves to practical work after learning AutoCAD 2000.

Master the skills

1, FAQ

(1) Draw the same picture. Some students draw the same picture in a moderate size, while others draw it so small that they can't even see it. Why?

This is because the boundary setting operation of the drawing area has not been completed, or even though it was set by using the LIMITS command, I forgot to rearrange the drawing area by using the ALL option in the ZOOM command. The setting of drawing area is based on the actual drawing needs.

(2) Some students draw a line segment with the name "hidden", but they find that the drawn line segment looks like a solid line. What is the reason?

This is caused by improper "linear scale", that is to say, the "linear scale" is too large or too small. The solution to the problem is to open the dialog box of the production line manager and modify its "global scale factor" to an appropriate value.

(3) After dimensioning, it is sometimes found that the dimensioning text cannot be seen. What is the reason?

This is because the overall scale factor of the dimension is set too small. Just open the dialog box of dimensioning method and change its value to be larger.

The above three problems are just the three most typical problems and difficulties my classmates encountered in the process of getting on the computer. There are countless practical problems. As a student, it is necessary to know these problems deeply, which is very helpful to improve the quality and efficiency of drawing.

2, there is comparison and identification.

Easy to confuse orders, pay attention to let yourself understand the difference between the two. Such as scale, translation and movement, segmentation and measurement.

3, the level should be clear.

Layers, like transparent overlays, can be used to organize different types of graphic information well. In the learning process, in order to save trouble, students directly select entity information such as color, line type and line width from the drop-down list box in the object property toolbar, which is very bad and makes the information processing in graphics not so easy. We should pay special attention to correcting this bad habit of ours. Strictly stratified and standardized drawing. My experience is: form good habits and benefit a lot.

4, the thickness should be clear

Being able to display the line width of entities is a new function of AutoCAD 2000. Using line width, you can clearly display the cross section of components, the depth of elevation, the dimension line and the thickness of different objects with thick lines and thin lines. As a student, you must specify the line width across the layer and display the line width. Improve your drawing quality and expression level.

5. There are differences between inside and outside

Using the "block" and attribute functions of AutoCAD 2000 can greatly improve the drawing efficiency. "Blocks" can be divided into internal blocks and external blocks.

An internal block is a block defined in a file and can move freely inside the file. Once the internal block is defined, it will be stored and opened at the same time as the file.

The external block writes the main file of the "block" to disk, and other graphics files can also use it. Please note that this is an important difference between external tiles and internal tiles.

6. It is waterproof.

Special attention should be paid to the fact that the entities that form the boundary of the shadow area must intersect at their endpoints, that is, they should be closed and "watertight"; Otherwise, wrong padding will occur. As a student, it is best to learn how to find "loopholes" and fix mistakes.

7. Writing should be standardized

Text is an indispensable part of engineering drawings, such as dimensioning text, drawing description, notes, titles, etc. Words and graphics together express a complete design idea. Although AutoCAD 2000 provides powerful word processing functions, it does not directly provide words that meet the engineering drawing specifications. Therefore, we should learn to establish a standard text of "long imitation of Song Dynasty". The concrete steps are as follows: open the dialog box of "Text Style", create a new style, which can be named "Long Imitation Song Style", change the font name in the dialog box to "Imitation Song Style GB-23 12", and change the width ratio to 0.67. The text of the dimension can be changed to "italic.shx" instead of "imitation song GB-23 12".

Another simpler way to use standard text is to directly use the "engineering word" style provided by AutoCAD 2000 template file; Note that AutoCAD 2000 should be started by "using templates" before use, and the national standard title (such as GBA3) should be selected to enter the drawing state. Then set the "Project Word" style as the current working style. This method is not mentioned in most textbooks, so students should pay attention to supplement this kind of training.

8, special people, special treatment

In actual drawing, it is often necessary to input some special characters, such as angle symbols and diameter symbols. These are all input with the control code provided by AutoCAD, which is relatively easy to master.

Other special characters, such as "τ", "α", "δ" and other Greek letters, are not so easy to master. It needs to use the "Other …" option of the MTEXT command to copy Greek letters in a special font and then paste them into the writing area. Pay special attention to editing such as font conversion.

There are also some special characters, such as "φ", which are widely used in mechanical drawing, called dimensional tolerance marking of up-and-down deviation, and can also be realized by the "stacking" function of MTEXT command. This is much more convenient than adjusting the corresponding function values in the annotation dialog box. My personal experience is: especially convenient!

9. If you don't follow the rules, you are not Fiona Fang.

Engineering marking is an important basis for parts manufacturing, engineering construction and parts assembly. Engineering notes are an indispensable part of engineering drawings at any time. In some cases, engineering annotation is even more important than graphics.

Many of my classmates are afraid of painting and labeling; One of the reasons is that there are too many dialog box options for labeling methods, which I can't see clearly and I don't know how to cooperate, so it is often difficult to achieve the ideal labeling effect.

To this end, in addition to understanding the meaning and common values of the options in the dialog box, you should also urge yourself to follow the following five rules when learning:

1. Create an independent layer for dimensioning, so that it can be separated from other information in the drawing and convenient for various operations.

2. Establish a special text style (such as the aforementioned "Long Imitation Song Style") and size for the size text.

3. Set the dimension unit to the required measurement unit, and set the accuracy to the minimum required unit.

4. Use the Size Mode dialog box to set the overall scale factor as the scale factor when drawing a graph.

5. Make full use of the target capture mode to quickly pick up the search points.

10, two spaces, two functions, two exercises

There are two kinds of spaces in AutoCAD 2000 environment: model space and drawing space, and their functions are different. Generally speaking, the model space is a three-dimensional space, which is mainly used to design the geometry and graphics of parts. Designers usually complete their main design ideas in the model space. The drawing space is used to express the geometric model on the engineering drawing and is specially used for drawing. Paper space, sometimes called "layout", is a paper space environment, which simulates paper pages and provides intuitive printing settings. At present, the design direction is to enter the modeling and design of three-dimensional parts, so when the parts need to be expressed on the designed engineering drawings, they need to be projected from all angles, dimensioned, and added with title bars and drawing frames. At this time, it is inconvenient to do these operations in model space, but it is convenient in drawing space. You can create viewport objects and place them in paper space, and you can add title blocks or other geometry. You can create multiple layouts in a drawing to display different views, and each layout can contain different print scales and paper sizes. The graphics displayed in the layout are exactly the same as those printed on the drawing page.

In order to let oneself deeply understand the function of "drawing space", when studying, we should give at least two practical examples to consolidate the concept of "drawing space" according to the requirements of teachers. Don't be lazy!

1 1, 99 is one

The goal of computer drawing is to make the design results play a role in production practice. At present, the design results basically enter production in the form of paper drawings. At the same time, in the design unit, paper drawings are also the main object of drawing file management. Although the development direction of computer-aided design is to realize paperless design and production, except for a few giant manufacturing enterprises, most ordinary design and production units still take paper drawings as the basis for organizing design and production. Therefore, how to convert the electronic format drawings designed and generated by AutoCAD 2000 into paper format drawings with specified format is a problem closely related to production practice. In a sense, this step is as important as the drawing process such as graphic modification and editing.

Therefore, in the study of "printing", in addition to understanding the use of dialog boxes, we should also actively participate in a demonstration class organized by teachers, so that we can truly feel the last link of "computer drawing".

To sum up, learning is not enough. AutoCAD also has many practical functions, especially some three-dimensional functions. There is no end to learning. As long as you are good at summing up in your study, you will certainly find the best learning method.