Blocks can be modified and when you modify a block, all cases of that block will change in the drawing. To explain this, I will use the door block that we created at the beginning of this chapter.

The door block we used contained a simple rectangle for the door and an arc representing the swing direction, shown in drawing A in the following figure. We want the block to change into the block shown in drawing B, with lines showing the wall distance and wall thickness, along with a dashed line along the length of the wall:

Let's see how to modify the block in the Block editor environment:

1. Open the drawing that contains the "Sample Door" block and insert this block in the drawing area.
2. Double-click on this block and select its name from the Edit Block Definition window that pops up and click OK.
3. The block will open in the block editor environment, which has a gray background and a tab that says Block editor, as shown:

4. In this environment, the block will work like a normal drawing object and you can make changes to your block here. Switch to the Home tab to make modifications to this block, as per door block B.
5. When you are done making changes, click the Close Block Editor checkmark at the end of this panel and select "Save the changes" from the pop-up notification.
6. The block will be modified and all cases this block will also change in the drawing. If you insert the block again, it will be added with a modified form.

Modifying the block in the block editor is not the only way of making changes to your block; you can also modify the block right inside your drawing. To make changes inside your drawing, select the block then right-click and select Edit Block in-place. You can also select Block Editor if you want to modify the block inside the block editor environment, as shown here:

When you select the Edit Block In-place option, AutoCAD opens a block selection window, where you can select the block you want to edit, and then click OK. The block opens right inside the same window and you can make changes to your blocks just like with a normal object. Once you are done making changes, click the Save Changes icon, which is now available at the end of the Home tab, as shown:

The block will be saved with the modifications and if you add a new reference of the block, it will add the modified version of it.