In simple terms, we can look at drawings as different lines connected. However, the shape of a line gives it a different meaning. The following table shows the most common types of lines we will see at this point. We will introduce more line types at later stages:
|
Type and shape of the line |
Line indication |
|
Visible object lines  |
Shows the visible outline of the object. |
|
Hidden line  |
This shows the hidden outline of the object from the drawing's viewpoint. This includes any details that are at the back of the object. |
|
Centerline  |
This indicates the center of any two entities. For example, the center of two edges and the center of a circle. |
|
Dimension line  |
This line is not part of the object; rather, it indicates the dimension of a drawing entity. Note that dimension lines are much lighter in comparison to visible object lines. |
|
Break line    |
This indicates a break in the object in the drawing. This is often used to fit relatively long objects within a drawing such as long construction beams. Note that there are many different types of break lines. The three types shown here are the most common ones. They are jagged cut, zig-zag cut, and small zig-zag cut, as seen from left to right. |
|
Section / hatch lines  |
Section lines are inclined lines indicating a cut in a section. We will see them in section views. |
The following drawing highlights a model and its 2D drawing. All the lines in the table are highlighted in the following drawing for easy reference:
Note that when we create drawings with SOLIDWORKS, the software will generate all those lines according to the international standard. However, it is important for us to be able to identify the different types of lines when we see them. Now that we know how to interpret lines, we can start learning how to interpret views.