In this lesson you will be introduced to blocks. By definition, a block is a collection of objects (lines, arcs, circles, text, etc.) that form a more complex entity that normally represents an object in the real world, e.g. a door, a chair, a window, a computer.
There are many advantages to using blocks, here the major ones:
Blocks are a single entity. This means that you can modify (move, copy, rotate) a block by selecting only one object in it.
You can build up a library of blocks consisting of the parts that you require many times in your workday. These blocks can be stored in a separate folder and even on a network so that all drafters have access to them. Think of plumbing parts, valves, elbows, etc.
Using blocks can help keep your file size down. AutoCAD stores block definitions in its database. When you insert a block, AutoCAD only stores the name of the block, its location (insertion point), scale and rotation. This can be very noticeable in large drawing.
If you need to change something, you can redefine a block. For example, you draw a chair and turn it into a block. Later, you’re told that the size of the chair has changed. Since you used a block you can redefine the block and all of your chairs are updated automatically. If you had drawn (or copied) 100 chairs in your drawing, you would have to manually change each one.
Blocks can also contain non-graphical information. These are text objects called attributes. For example, you have made blocks of different chairs. You can add information to the block such manufacturer, cost, weight, etc. This information stays with the block, but can also be extracted to a database or spreadsheet. This would be useful for things such as a bill of materials. Attributes can also be visible or invisible in your drawing. Another good use of attributes could be a title block.
You can even easily add internet hyperlinks to blocks so you can connect a block to a page on a supplier’s online catalog.
There are two types of blocks you can create: blocks that are internal to your current drawing, and those that are external, or saved as a separate file. To create the different types, different commands are used. Many companies use a template that will include a number of blocks for use in the project.
Here are the commands that you will need for using blocks in this lesson:
|Block||Bmake / B||
|Home > Block > Create||Creates a block from separate entities (internal to current drawing)|
|Write Block||Wblock / W||
|None||Creates a block and writes it to a file (external)|
|Insert||Insert / I||
|Home > Block > Insert||Inserts a block (internal or external)|
|Explode||Explode / X||Home > Modify > Explode||Explodes a block or other compound object into its component parts|