As the name indicates, this Object Snap will let you make lines parallel to another line. To use this snap, make sure it is active in the status bar, as shown:

In the following example, I will make a line parallel to the existing inclined line using the Parallel Object Snap option:

1. Make a line that is inclined to any angle, as shown:

2. Now, select the Line command again and click at any point to start the line. Now, move your cursor close to the existing line and then move it out so that it becomes parallel.
3. Once your line becomes exactly parallel to the existing line, a Parallel Object Snap, as shown in the following figure, will show up. You will also notice a green tracking line to guide you to make a parallel line:

4. Just click at any point along this green tracking line to make a line that is parallel to the existing line. This Object Snap option is also not used often and it is recommended to keep it off when not required.

So, these were the Object Snaps that help make precise drawings. Though you may be tempted to keep all of these Object Snap options active, I would still strongly recommend against it and suggest you keep only the most often used Object Snaps active as it will avoid conflict between many snap points, thereby avoiding errors in your drawing.

There is also another way of using these Object Snap points—with the help of Object Snap overrides—which we will discuss in the next section.