How to convert a single-line diagram into a double-line diagram in cad

In CAD, you can't convert a single-line drawing into a double-line drawing. When drawing, you can only use the multiline command to draw. The specific method is as follows:

1. Open a CAD document in your computer, then find "Drawing" in the menu bar above, and then click "Multi-line" in the open list:

2. Then you can draw with the mouse, as shown below:

3. Because the drawn graph cannot be closed directly under the multi-line command, enter "c" in the command bar below and press Enter to confirm:

4. In this way, the drawn graph can be closed, as shown below: