AutoCAD. A block is a collection of objects combined into a single named object. A block can be a realistic representation of an object or a simple symbol like what is used in a schematic. Blocks could be stored locally or globally. In this example, we'll be creating global blocks, which are external files using attributes. Local blocks are available in the active drawing. You can use the Blocks palette to access blocks and other drawings to bring them into your current drawing. You can use block attributes to store information about the objects included in the block. An attribute is a label or tag that attaches data to a block. Attributes can include information such as manufacturer, part number, fire rating, and description. You can view a summary of the information for all the blocks in a drawing using the BCOUNT Express Tool or BATTMAN. The best thing about attributes is that they can be easily modified and updated. AutoCAD allows you to create tool palettes that link to your blocks to make it easier for you to access and use the desired content. If you use a tool palette to access your blocks, it's important to understand that the palette is linking to the external block files. If those files are moved or deleted, the block tools on the palette will no longer work. For this reason, many users prefer to use the Autodesk Design Center. They use the Autodesk Design Center to bring blocks into their active drawing. In this example, I have an electronic control panel. I want to create a block for the relay. I want to define three attributes. The reference designator, the manufacturer, and the manufacturer part number. I don't need the manufacturer and manufacturer part number to be visible. So those will be invisible attributes. I like to use invisible attributes, because then I can extract that data into Excel spreadsheets. To extract the attribute information in your drawing, use the ATTEXT command. I want to convert the relay geometry into a block along with the attributes. I start by defining the attributes. That attribute tool is located on the block definition panel on the Insert tab. I select Define Attributes. The tag field cannot have any spaces, but I can use an underscore instead of a space if I prefer. I type in REFDESIGN for reference designator. The prompt is the field that the user sees that attribute dialogue for the block. I type REF DESIGNATOR for the prompt. For the default, I type R1. I usually put something in the default field to indicate the format I want the user to use. I set my justification to middle and my text type to 1. Notice that I have my insertion point enabled to specify onscreen. This is one of the biggest errors users make. They forget to designate an insertion point. By default the insertion point is set to 0, 0. So if you don't see your attribute, it is likely that that's where it is. You can locate the attribute and move it to the desired location. I click "OK" to place my first attribute. I can move the attribute once it's placed to adjust its position. I'm going to draw a line to help me locate my attributes so it looks okay. You see the attribute tag. It looks really big, but remember the actual value of the attribute is only going to be two or three characters. I right-click to select the ATTDEF command under Recent Input. I enable invisible because my next two attributes will be invisible. For the tag, I type MFR for manufacturer. For the prompt, I type MFR. For the default, I type Automation Direct. I set my justification to middle and my text type to 1. I click "OK" to place the attribute. I use the midpoint of the line to insert the attribute. I right-click to select the ATTDEF attribute defined command under recent input. I enable invisible. For the tag, I type PARTNO, for the prompt I type PART NO, and for the default I type R700. I set my justification to middle my text type to 1. I click "OK" to place the attribute. I use the end point of the line to insert the attribute. I erase the line. It's time to create the block. This is going to be a global block. That means it will be written to an external file which can be placed on a server or e-mailed. I go to the block definition panel of the Insert tab. I select Write Block. I select the base point for the block. This is the insertion point to be used for the block. This is another common error users make. If you don't specify a base point, by default, the base point will be set to 0, 0. This means the block geometry can be located far away from the insertion point. I use the middle point of the bottom of the relay as my insertion point. I want to select the objects that will be part of my block next. I can just window around everything that is part of the relay, including the attributes. I'm going to enable Convert to block to convert the existing attributes and geometry into a block. I browse to where I want to save my block and give it a new name, RELAY R700. I click "Save". I always like to double check that the file name and path are correct before I click "OK". I look over the dialog to verify that I have selected a base point, that I have objects selected, and that a filename and path are specified. Then I click "OK". The attribute dialog comes up and you can see the attributes listed as they were defined. Note that you don't see the part number or manufacturer information in the block. This is because they were set to invisible. I click "OK". To see my invisible attributes, I type ATT DISP for attribute display. This command controls the display of invisible attributes. I select On. Now you see the invisible attributes. I right-click and select ATT DISP. I select normal to hide the attributes again. I want to add this block to a tool palette so I can easily access it in the future. I type tool palettes to launch the tool palettes. You can see that each tab has different tools that can be used in your drawing. Tool palettes come with AutoCAD. They are worth exploring to see if there is an existing tool that you might want to use. I right-click on the bar to create a new palette tab and call it Control Panel. Before I can add my block to the palette, I need to save my drawing. So I click "Save". Then I can just drag and drop the block onto the palette. Now this block is available for me to use in any drawing. Remember if I move the location of the block file, the link will be broken and it will no longer work from the tool palette. To insert the block, I just drag it from the tool palette into the drawing. I select an insertion point and then the attribute dialog will appear. I change the reference designator and click "OK". I repeat to fill in the remaining paths in the row. I just select the block from the tool palette, left-click on the mid-point of the empty path to place the block, fill in the correct reference designator, and move on to the next empty pad until I have six relays placed. I'm going to close the tool palette. If I wanted to change any of my attribute definitions I can use a tool called BATTMAN. That's the Block Attribute Manager. I type B-A-T-T-M-A-N for BATTMAN. The dialog appears. The dialog provides a list for each block, and you can see how many of each block is in the drawing. This can be useful information. So if your manager asks you how many of these relays are being used. You could bring up BATTMAN, and give him a quick answer. I highlight the reference designator attribute and click "Edit". Notice I can change the tag, the text options, or the properties. I'm going to change the color to yellow. All the blocks already in the drawing automatically update. I click "OK". I click "Apply" and "OK". Many users up to store all their blocks in a single drawing instead of using a tool palette. Then they can use the Design Center to access their blocks. To open the Design Center, you can type DC or ADC, for Autodesk Design Center. The Design Center opens and lists any open drawings. I select the Open tool at the top of the Design Center to open my block library drawing. I select the blocks folder to review the blocks available in this drawing. I locate the control block and I select it. I right-click and select Insert block. I enable Specify Onscreen. I keep the scale in rotation option disabled to accept the default values. I click "OK". I place the block in the desired location. The attribute dialog appears. I accept the default value, I click "OK". I close the Design Center. That was a whirlwind tour of blocks and attributes. Invisible attributes can be useful. To change the attribute display, don't forget the ATT DISP command. BATTMAN can be helpful to reorder your attributes or change your properties. Tool palettes can help you organize your blocks and make them easy to access and use. So don't forget the tool palette command. Use the Design Center to access other drawings where blocks are stored. Consider creating a central drawing where you store all your blocks in a single file to make it easy for you to locate and use your block library.
