Symbols

Insert symbols and details into your drawings from commercial online sources or from your own designs.

Some Basic Definitions

In AutoCAD, symbols and details that you insert into drawings are called blocks. A block is a collection of objects that are combined into a single named object. The following are some examples of a variety of blocks at different scales.

There are three elements involved for inserting blocks in a drawing.

• A block definition. This data is stored in a drawing file or drawing template file in a non-graphical format. Block definitions can easily be imported from any drawing file or existing blocks in any drawing file. You can also create block definitions from selected objects in the current drawing.
• A block reference. When you insert a block, the graphics are generated from the block definition.
• A block insertion tool. Several different tools are available in the product. These include the block gallery on the ribbon, the Blocks palette, the Tool Palettes window, and Autodesk Design Center.

For example, the following drawing contains four block definitions: Cubicle, Chair, Table, and Plant. There are three block references to Cubicle, twelve block references to Chair, two block references to Table, and two block references to Plant.

Note: The commonly used term, block, can refer loosely to either a block definition, a block reference, or both depending on context.

Insert Blocks into a Drawing

Typically, you insert a block into the current drawing from one of these sources:

• Any drawing file. For example, you might create a drawing of a standard detail view. You can then use one of the block insertion tools to insert this drawing as a block into your current drawing.
  
• One or more block definitions contained within a drawing file. For example, you can create a drawing that only contains block definitions of trees. You can then insert any of these blocks from that drawing into your current drawing. A drawing file that contains a family of related blocks is commonly termed a block library drawing.
  
• One or more block definitions created in your current drawing. For example, you might want to create a block from a set of objects that appear repeatedly in that drawing, such as a cubicle arrangement. All the blocks used in the cubicle arrangement be combined into a single block for multiple placements.
  

Once you insert a block, you can easily move, copy, rotate or scale it.

Use a Block Insertion Tool

To get started, follow these steps:

1. Click Insert from the Home tab and click Blocks from Other Drawings. This starts the BLOCKSPALETTE command.
   
2. At the top of the Blocks palette, click the Browse control to open the Select Drawing File dialog box.
   
3. Navigate to the DesignCenter folder where a variety of sample drawings are stored.
   

   Each of these drawings contain a set of related block definitions.

4. Select a drawing file that interests you.

   For example, let's say you create drawings for heating, ventilation, and air conditioning. Select the HVAC drawing and then click Open.

   
5. From the Blocks palette, Other Drawings tab, select and place or drag and drop several of the blocks.
   

To specify a different drawing file, use the Browse control as before.

Tip: The default options at the bottom of the Blocks palette are usually acceptable in most cases, but you can experiment with them to see what options you might want to use.

Notice that the next time you click Insert on the ribbon, the gallery displays all of the block definitions stored in the current drawing.

Also, familiarize yourself with the Blocks palette by clicking on the Current Drawing tab and the Recent tab.

• The Current Drawing tab displays all of the block definitions in the current drawing only.
• The Recent tab displays the block definitions that you've recently inserted or created in the current and previous sessions. These blocks can come from various drawings.

Create a Drawing for Use as a Block

Often, individual drawing files are created to be used as blocks and saved in a folder with similar drawing files. This method is an alternative to accessing the block definitions stored in a single drawing.

When you create a drawing file for use as a block, make sure that you locate an object at the origin point (0,0). This will serve as the default insertion point of the block. Later, when you insert the block, it is attached to your cursor at the insertion point. The insertion point is circled on the block below.

If you select a block that's already been inserted, it displays a grip at the insertion point. You can easily move and rotate this block using this grip.

In the following example, a drawing file is inserted into the current drawing to provide a standard detail view.

Custom title blocks and drawing borders are also created as drawing files that can be inserted later or included in drawing template files. Here's an example:

Tip: When you save the drawing, navigate to a folder, right-click, and create several folders to organize the block drawings. You can drag one or more of them into your Places bar for easier access in the future.

Note: Inserting a drawing file as a block provides a static reference to the specified drawing. For a reference that automatically updates when it's changed, you would attach the drawing as an external reference instead. For more information, search the Help system for xrefs.

Manage Block Definitions and Data in a Drawing (Optional)

You can create, remove, and modify block definitions directly in the current drawing for special circumstances.

• Remove unused block definitions from a drawing with the PURGE command. Purging a drawing of unused block definitions can reduce the size of a drawing. You can purge only those block definitions that aren't used by any block references in the drawing.
• Create new block definitions directly in the current drawing with the BLOCK command. Creating block definitions is useful either if you need a block that's unique to that drawing or if you want to create a block library drawing that contains a family of related block definitions.
• Disassemble a block reference into its constituent objects with the EXPLODE command. Exploding block references provides an easy way to define new versions of a block definition with the BLOCK command or to save the resulting objects to a new drawing file with the WBLOCK command.

Tip: Block definitions can also include objects called block attributes that can store information such as part number, vendor name, and cost. You can extract and export block attribute data to a table, schedule, or external file. Some blocks called dynamic blocks can change their appearance dynamically depending on data entered, location, or options chosen.

Suggestions and Recommendations

Several different methods are commonly used for saving and organizing block definitions.

• Create an individual drawing file for each block that you intend to use. You save these drawing files in folders that contain families of related drawing files.
• Create drawing files called block library drawings. Each one of these drawings contains a family of related block definitions. When you insert a block library drawing into your current drawing, all the blocks that are defined in that drawing become available to your current drawing.
• Include the block definitions for title blocks and commonly used symbols in your drawing template files to make them available immediately when starting a new drawing.
• Evaluate which block insertion tool best suits your needs: the Blocks palette and ribbon gallery, the Tool Palettes window, or Autodesk DesignCenter.

Tip: With online access, you can download AutoCAD drawing files from the web sites of commercial vendors and suppliers. This option can save you a significant amount of time, but check to make sure that these drawings are drawn correctly and to scale.