Organizing drawings with AutoCAD - 5 Section

CHAPTER 23: BLOCKS

In architectural plans, it is often necessary to draw something that is repeated incessantly. For example, in a floor view of a movie room, the architect is required to draw each of the seats. In the plans of a hotel, to mention another case, each room has its sink, toilet, bed, shower, tub, etcetera. And most of these elements are the same to each other. And although it is true that we have already seen how to create a group of objects and that copying it to locate it in another position is no problem, we will study here an alternative method that has great advantages over the use of copied groups.
Blocks are also groups of objects that behave as one. They are defined as blocks because, once created, each block insert we make in the drawing is actually a reference to a type block that is saved with the file, so that if we insert that block dozens of times in a drawing and then we need to modify it, just change the definition of the block and all the references that depend on it will be modified automatically. So, if you insert a block for a washbasin on the plans of a hotel and then correct it, the washbasins in all rooms will be corrected as well.
With the use of blocks we also avoid that the file is bigger than necessary. Autocad only records the block definition once and then only the data of all the inserts in the drawing. If we used groups copied, the file would contain all the data of each group, with what the size of the file would grow in an important way. A final advantage is that the blocks can be recorded independently of the drawing, so they can be used in other jobs. In fact, if you search for resources for Autocad on the Internet, you will find that many, many pages give you block files for a large number of uses. If you dedicate a couple of days to download these files, you will see that in a very short time you will have a fairly large block library.
But let's see how to create and use the blocks, what particularities they present with regard to layers, how to edit them and how to convert them into files for other drawings.

23.1 Creating and Using Blocks

Once you have drawn the objects that are going to form a block, we use the Create Block button in the Block Definition section of the Insert tab, which opens a dialog box where we must indicate the name that the block will have, what objects it consists of and what will be its base point, that is, the reference point to insert it. It is also necessary to indicate what unit of measure the block will have if inserted in other drawings. This part makes sense when using the Design Center, which will be the subject of a later chapter. Once the objects have been selected, we must decide whether they will remain in the drawing, become the first reference to the block or simply be deleted. Finally, we can select whether the block will have active the annotative property to which we have referred repeatedly, whether to apply a uniform scale and whether or not the block can be decomposed into its original objects with the command of the same name in the Modify section . When you click OK, the definition of a block is completed.

Once the block has been created, we can insert it again in our drawing with the Insert button in the Block section of the Insert tab. This opens a new dialog where we can see the list of blocks defined in our file. In it we can also choose the point where to insert the block, its scale and angle of rotation, although it is very likely that you decide to define each of these elements directly on the screen.

This same dialog box allows us to insert other drawings as blocks in the current drawing, using the “Browse” option, so that we can take advantage of other drawings that we have created.

Blocks created in a drawing can be recorded as separate drawing files so that they can be used in other works. This can also help us create a library of blocks for all needs.
The Write Block button in the Block Definition section of the Insert tab saves blocks as “.DWG” files. The dialog box is practically identical to the one used to create the blocks and can even be used that way, only it also adds the section to indicate the destination of the file.