Types of Lines in Engineering Drawing

Published by GayaMadhusanka on

Engineering Drawings are some kind of language to represent the engineer’s ideas. Various symbols, line types, notations, and patterns in the engineering drawings. When considering the lines, There are different types of lines in engineering drawing. Each line type gives different meanings and is usually used for various purposes. As an example, thick lines are normally used to highlight some locations in drawings. However, understanding these line types will help you read the engineering drawings properly.

Different CAD Design software has additional facilities for drawings. Some of the software provided facilities to create custom drawing lines as well. However, there are basic line types for engineering drawings. But depending on the industry application of the lines are different.

Different Types of Lines in Engineering Drawings

In different engineering disciplines and different engineers are using their unique lines and drawing patterns for their drawings. For example, HVAC Engineers are using different drawing types and notations compared to Product Design Engineers. However, there are different types of lines in engineering drawing and you can select lines according to your requirements.

Types of Lines in Engineering Drawings

Object Lines

To represent the objects in their edges you can use Object Lines. These are thick and continuous lines. Commonly used for the edges of objects to get clear visibility.


Center Lines are indicating the central axis or symmetry of the objects. In Some design software, there are no differences between center lines and construction lines.

Different Color Lines

You can use different colors according to drawing requirements. If you are an electrical engineer color lines are really necessary for electrical wiring.

Different Color Lines in Engineering Drawings

Different Thickness Lines

There are different thickness lines and you can use different pictorial representations.

Different Thickness Types of Lines in Engineering Drawings

Different Line Applications for Mechanical Drawings

Engineering designers and draftsmen use different lines to represent different meanings. Here there are some examples.

  • Section View
  • Break View
  • Hidden Lines

For each of these applications, we usually use different line types. The following is a detailed description of the above applications.

Section View

To represent the internal details of an assembly or a part, you can use section views

Section View in Engineering Drawing

Break View

If your drawing parts are too large and you need to get them into the drawing space, you can use Break Lines.

Break View in Engineering Drawings

Hidden Lines

If you need to represent internal details of parts or an assembly you can use hidden lines. Most of the Product Design software has facilities for hidden lines. Line lines are not only drawings. It can be used to identify the internal details of 3D models as well.

Hidden Line of Hole


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