CAD Basics * Tips: Summary of Various Operations and Concepts Related to Blocks (Part 1)

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When using the HaoChen CAD software to create drawings, it is sometimes necessary to insert certain special symbols for use in the graphics, and this is when the block and block attribute functions come into play. Those who are just starting to learn CAD may not be very familiar with how to use blocks and attribute functions for drawing. Next, I’ll share some tips for learning CAD related to blocks! I. Characteristics of CAD blocks CAD blocks refer to a collection of graphic entities; within such a graphic unit, each entity can have its own characteristics such as CAD layers, line styles, and colors. During application, CAD treats blocks as independent, complete objects. Users can insert blocks at any specified location in a certain proportion and angle as needed. Since the block is inserted as a single entity, CAD only saves the overall characteristic parameters of the block, without the need to save the characteristic parameters of each individual entity within it. Therefore, when drawing relatively complex graphics, using blocks can **save disk space**. Modifying blocks can also bring significant convenience to users’ work; if a defined block is modified or updated, the system will automatically update all instances of that block in the current drawing. II. Methods for creating CAD blocks: Menu command: [Draw] → [Blocks] → [Create]. Toolbar: [Draw] → [Create Block]. Command line: BLOCK. Shortcut key: B. Blocks created using the BLOCK command are often referred to as internal blocks; they are saved along with the graphic file that defines them, meaning the blocks are stored within the graphic file itself. Internal blocks are generally used for invocation within that graphic file. After executing the BLOCK command, the system will open the [Block Definition] dialog box, through which blocks can be created. The meanings of the various options are as follows: ① Name box: Defines a name for the CAD block. The name can contain up to 255 characters, including letters, numbers, spaces, and Chinese characters. Block names and block definitions are saved in the current drawing. ②Base point field: Used to specify the insertion base point for CAD blocks; if no base point is specified, the system defaults to the coordinate origin. ③Object bar: Click the ‘Select Object’ button (or the ‘Quick Select’ button) there to select the object that defines the CAD block. There are also three single-choice options in this field, whose meanings are as follows: Ø Keep: Retain the source object after creating a CAD block, that is, do not change any parameters of the object that defines the block. Ø Convert to block: After creating a CAD block, the source object is automatically converted into a block. Ø Delete: The source object is automatically deleted after a block is created. ④Settings bar: The meanings of the various options are as follows: Ø Block unit: Specifies the unit for inserting block references; it is usually millimeters, but other units can also be used. Ø Hyperlink: Clicking this button will open the [Insert Hyperlink] dialog box, which is used to set a hyperlink for the defined block. ⑤Method bar: Used to specify the behavior of a block, including the following options. Ø Annotation: Selecting this option allows you to create an annotation block reference. Annotation block references and attributes support the current annotation scale at the time of their insertion. Ø Align the block direction with the layout: Specify that the direction of the block reference in the CAD drawing space viewport should match the direction of the layout. If the “Annotation” option is not selected, it is unavailable. Ø Scale by uniform ratio: Used to determine whether the blocks should be scaled by a uniform ratio. If the “Commentary” option is selected, this option is unavailable. Ø Allow decomposition: Used to determine whether the [Decompose] command can be used to decompose CAD blocks. ⑥Note: Used to add explanatory information to the block. ⑦Open in Block Editor: Used to determine whether the block should be opened for editing within the block editor after it is created. III. Command line for writing a block (i.e., saving a block to disk): WBLOCK. Shortcut key: W. After executing the WBLOCK command, the system will display the “Write Block” dialog box. Through this dialog box, the defined CAD blocks or selected objects can be saved to the disk in file format. Blocks created using the BLOCK command are stored within the graphic file; they are not separate files and generally cannot be applied to other graphic files. Using the WBLOCK command allows a block to be saved as a separate file, which can be used by any graphic file. The meanings of the various options in the [Write Block] dialog box are as follows: ① Source field: Used to select the object for which the block file will be created. Among them: Ø Block: Used to select a predefined block name from the drop-down list. Ø Entire graphic: Save all graphics in the drawing area as blocks. Ø Object: Save the graphic object selected by the user as a block. ②Base point: The same as the [Block Definition] dialog box. ③Object: The same as the [Block Definition] dialog box. ④File name and path: Specify the name of the file to which the data will be written and the location where it will be saved. IV. For CAD software output blocks, execute the [File] → [Export] command to open the [Export Data] dialog box; select the “Block” type from the save type list. This operation allows the entire graphic to be saved as a block file, or the blocks defined within the graphic to be saved as separate block files. V. CAD nested blocks: A nested block refers to a CAD block that contains other blocks. For example, an assembly diagram of a mechanical component can be inserted as a block; this component includes a frame, brackets, and fasteners, with the fasteners themselves being blocks composed of screws, washers, and nuts. VI. CAD attribute blocks are labels or markers that attach data to a block. The data that may be included in the attributes includes part numbers, prices, notes, and the owner’s name, among others. Tags are equivalent to column names in a database table. Design firms typically use attribute blocks to define elements such as title bars and signature areas within drawing frames. Everyone uses the same drawing frames, but it is possible to edit attributes like the drawing name and scale according to the specifics of each drawing. The attribute text must be defined separately first; then, when defining the block, the graphic and the attributes are selected together, thus creating an attribute block. Attributes can also be “invisible”. Hidden attributes cannot be displayed or printed, but their attribute information is stored in the graphic file and can be written to an extraction file for use by database programs. VII. CAD anonymous blocks (nameless blocks) are CAD blocks generated by custom development programs; when such blocks are selected, an asterisk will appear in front of the block name in the property box (Ctrl+1). When inserting blocks, these blocks cannot be found in the list. Anonymous blocks cannot be edited using the refedit and block editing functions. Anonymous blocks can only be exploded for editing. If it’s an anonymous block combined with multiple insertion blocks, it becomes quite troublesome – it cannot be broken apart or edited. The above introduction covers the operations and concepts related to blocks in the Haochen CAD software. Those who are just starting to learn CAD should definitely take a look at it; mastering these concepts can greatly help improve drawing efficiency.