Organizing drawings with AutoCAD - 5 Section

23.2 Block edition

As we already mentioned, a block can be inserted in a drawing many times, but it is only necessary to edit the reference of the block so that all the inserts are modified. As is easy to conclude, this implies a very important saving of time and work.
To modify a block, we use the Block Editor button in the Block Definition section, which opens a special working environment for modifying the block (which is used to add attributes to the dynamic blocks), although you can use the commands of the Ribbon to make your changes. Once the reference to the block has been modified, we can record it and return to the drawing. There you will notice that all the inserts of the block have been modified too.

23.3 Blocks and layers

If we simply create blocks for small symbols or representations of simple objects, such as bathroom furniture or doors, then perhaps all the objects in the block belong to the same layer. But when the blocks are more complicated, such as three-dimensional pieces of installations or plan views of foundations with dimensions, rods and many other elements, then the objects that compose it are likely to reside in different layers. When this is the case, we must take into account the following considerations regarding blocks and layers.
First, the block as such will reside in the layer that was active at the time of creation, although its constituent objects are in other layers. So if we disable or disable the layer where the block is, all its components will disappear from the screen. Conversely, if we deactivate a layer where only one of its parts is, then only the layer will disappear, but the rest will remain present.
On the other hand, if we insert a saved block as a separate file and if this block has objects in several layers, those layers will be created in our drawing to contain those elements of the block.
In turn, the color, type and line weight properties of a block can be set explicitly with the toolbar. So if we decide that a block is blue, it will remain constant in all block inserts and the same happens if we explicitly define the properties of its individual objects before converting them to a block. But if we indicate that these properties are "By layer", and if this is different from layer 0, then the properties of that layer will be the properties of the block, even when we have inserted it in other layers. If we modify, for example, the line type of the layer where we create the block, it will change the line type of all the inserts, in whatever layer they are.
In contrast, layer 0 does not determine the properties of the blocks created on it. If we make a block on layer 0 and set its properties to “By Layer”, then the block's color, type, and lineweight will depend on the values ​​these properties have on the layer they are inserted on. So a block will be green on one layer and red on another if those are their respective properties.