AutoCAD Block 01

6.4.1 Block profile

Before introducing the concept of block, let's recall some of the problems encountered in manual drawing. For example, when drawing electronic circuit map, need to draw a large number of resistors, capacitors and other components, and each type of components are basically the same shape, in other words, have to do a lot of repetitive work. This problem is more or less the same in other areas, such as doors and windows in building drawings, valves and connectors in piping diagrams, etc. For this type of problem, AutoCAD also provides a very ideal solution for a number of frequently reused objects grouped together to form a block object, saved by the specified name, and can be inserted into the graph at any time without redrawing.

Although a block can be composed of multiple objects, it is used as a whole. Users can view a block as an object to operate, such as "move", "Copy", "Erase", "rotate", "array", and "mirror" commands. Of course, if necessary, you can also use the "explode" command to decompose blocks into relatively independent multiple objects.

When the user creates a block, AutoCAD stores the block in the graphics database, so the user can insert the same block multiple times as needed without having to repeat the drawing and storage, thus saving a lot of drawing time. In addition, the insert block does not need to replicate the block, but only according to a certain position, scale and rotation angle, so the amount of data is much smaller than the direct drawing, thus saving the computer's storage space.

In addition, in AutoCAD, the block can also be stored as a separate graphic file, also known as an outer block. So that other people can insert the file as a block into their own graphics without having to recreate it. Therefore, a graphical symbol library can be established in this way for all relevant designers to use. This not only saves time and resources, but also guarantees the unity and standard of symbols.

Creation and use of 6.4.2 instance 2 block

Step 1 Create a new graphics file

Start the AutoCAD 2002 system and create a new graphics file for the template "ACADISO.DWT".

Step 2 draw an identification point

(1) Call the "line" command to draw two lines between the point ( -1,-1), the point (1,1) and the point ( -1,1), the point (1,-1).

(2) Invoke the "circle" command to draw a circle with a radius of 1 at the center of Point (0,0).

(3) Call the "Donut" command, with a point (0,0) as the center, draw a ring with an inner diameter of 0 and an outer diameter of 2. The result is shown in Figure 6-14.

(4) Then use the "trim" command to trim the ring. Call the trim command and select two lines to trim the border, removing the One-fourth and below One-fourth sections of the ring. The result is shown in Figure 6-15.

Step 3 Creating a Block object

(1) Create a block object using the completed identification point graph. Select the icon in the Draw toolbar to eject the Block Definition dialog box, as shown in Figure 6-16. and make the following settings:

Enter the block name "Sign_point" in the name edit box.

Set "Base point" three-dimensional coordinates (0,0,0).

In the Objects column, click the icon to return to the plot area and select all drawing objects. and select the Convert to block item.

In the Preview icon (preview icons) column, select the "Create icon from block Geometry (icon created from the geometry of blocks)" item.

To keep the other settings unchanged, click the OK button to end the Create block command, thereby creating a block object named "Sign_point".