What Is a Drawing in Engineering? (And How to Create One)

By Indeed Editorial Team

Published June 10, 2022

Engineering drawings typically contain all the necessary pictorial information during an engineering or construction process. It's usually the first drawing before other technical diagrams in a project. As a construction professional or someone interested in engineering, understanding how these diagrams work can be beneficial. In this article, we discuss engineering drawings, explain their purpose, discuss their elements, explore their projections, share how to create these diagrams, and review their uses.

What is a drawing in engineering

A drawing in engineering is the starting point for engineering projects because they visually represent the aim of the project. Engineers and drafters create a digital model of the desired building, display it from various angles, and label it with information to make further technical drawings on paper. An engineering drawing depicts a product's dimensions, shape, irregularities, and other details that can aid in a thorough understanding of the project.

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The purpose of an engineering drawing

These drawings are essential in the construction or engineering process. Engineers design and send the diagrams to the manufacturing department to create the machines or instruments needed. After the creation, they send the drawings to the assembly department to guide them in coupling the parts or the machine. The detailing of the engineering drawing can help ensure that the measurements, dimensions, system geometrics, functionality, hardware, and finish are as accurate as possible.

For example, electronic designs may include information such as which components to wire or fuse. Structural engineering or architectural diagrams may incorporate details about how a building or mechanism works with the terrain. Drawings also offer a significant degree of information on how companies can build an item, including components of the product where precision is vital and the project's margin for error. This amount of detail is feasible because engineering illustrations adopt specific international norms that help engineers comprehend what the drawing intends.

Why is it essential for engineers to know how to draw?

It is necessary for engineers and drafters to have the drawing skills to transmit their design specifications to the production department effectively. It's also essential to be able to illustrate their ideas for proper documentation and application for patents. A computer-aided design (CAD) can help reduce the engineer's burden to draw from scratch. CAD software makes 3D figures of usual machine parts and allows engineers to alter them by inputting their specific dimensions and adjusting them. With CAD software, engineers can readily make their computer models quickly and accurately.

CAD software has replaced the old-fashioned method of engineers drafting these diagrams by hand. Some companies have drafting departments that use a specific CAD application to make the designs, which are highly detailed and industry-specific. Engineers then correct or modify these diagrams using their expert knowledge. The technicians and drafters in these departments typically have considerable training in CAD software and related systems. Drafting professionals may specialize in structural, electrical, civil, or architectural diagrams.

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Elements of engineering drawing

Depending on the industry and the purpose of the drawing, technical drawings can have a variety of elements but contain some key ones. These are some vital elements of an engineering drawing:

  • Drawing field: The drawing field is the area that contains the diagram. Engineers can manipulate the drawing field to view the drawing from different angles or perspectives.

  • Title block: This section of the drawing is a little box that contains information about the diagram and draftsman. It includes the title of the drawing, its dimensions and measurements, and some intellectual property comments, if available.

  • Revision block: This area contains a short record of changes in the drawing. It's usually at the top right corner of the drawing area or close to the title block and holds information about alterations in the date and design of the drawing.

  • Materials or parts list: This section includes details on the parts required for the construction and assembly of the machine or building. It also contains details of finishes and coatings for the equipment.

  • Zones: Zones are letters and numbers in the drawing area. You can quickly identify specific areas of a drawing using zones because they represent a grid with letters on one side and numbers on the other.

  • Notes: This section includes any additional detail on constructing, assembling, or using any specific part.

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Projections in an engineering drawing

Projections allow an engineer or drafter to show a three-dimensional object in the form of a two-dimensional graphic. Engineers can use a variety of projections in their drawings to display additional detail on a specific side or area, demonstrate components or steps involved in the diagram, or show the inside perspective of the assembly or building. For an accurate drawing, it's often essential to know how to utilize projections. Some typical projections for engineering drawings are as follows:

Oblique

In an oblique projection, the front part of the drawing appears to be facing away from the spectator, while the side at the bottom left of the drawing faces them. When you look at the part up close, the farthest edges appear shorter than they are because of how this projection displays the lines to scale. As a result, this kind of diagram may seem distorted.

Isometric

An isometric projection depicts an object at an angle with all of the object's visible sides facing the viewer simultaneously. Engineers can gain additional technical data about a drawing's dimensions with this view, which typically includes all lines drawn to scale. In digital form, the isometric projections can potentially distort the appearance of the part or machine, much like oblique projections.

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Orthographic and multi-view

An orthographic projection depicts an object from every angle. For instance, if you are looking at a cube, the orthographic projection can display what you can see from all sides. The first and third orthographic projection methods allow for different side view configurations. The third projection is the most prevalent in Canada, while the first projection is more common in overseas applications.

How to design a drawing in engineering

Engineers and technicians can design buildings, electrical systems, plumbing works, and heavy-duty machines by using CAD software and inputs. These are the steps engineers take to create an engineering drawing:

1. Structure the project

Engineers and draft technicians connect with design teams and gather all relevant planning papers before creating engineering drawings and blueprints in a CAD application. Before starting, they typically do extensive study to ensure that they completely understand the item's function and all of its characteristics. When using a CAD application, engineers use function instructions to apply specific product specifications.

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2. Create project files

After planning the project, engineers and drafters enter the specs of the product they want to create into a CAD project file. The project file may include parameters such as dimension and orientation depending on the engineer's preferences. Engineers use the digital tools and menus that they've stored in the project files when executing the project.

3. Create a drawing

While using the CAD program, engineers work with drafters and other design experts to begin product creation. To verify that all dimensions and materials are accurate, engineers supervise the digital design process during the development phase of the project. As the project progresses, engineers and designers also watch for any problems that may affect the final product.

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4. Add technical data

It's important to include technical and informative data such as the revision block, title block, and zones on the drawing. There may also be administrative comments regarding the company, project completion deadlines, and modifications included in a technical drawing's data. With this information on the diagram, other engineers, designers, and firm officials can revise and verify the accuracy of the drawings when reviewing them.

5. Gather feedback

Depending on the project, a drafter or an engineer may collect comments from other engineers, coworkers, and supervisors on the project. For larger projects, they may give a draft to the client for review before finalizing the job. Depending on the nature of the project, engineers may even conduct a series of tests to ensure that the product works properly before going into production.

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6. Approval

Engineers print or send digital versions of their technical drawings to upper-level executives or clients for review and approval before, during, and after the process. Engineers send out prototypes to get input on the design before it goes into production. They use this input to make adjustments and modifications to the design.

7.Post- evaluation

After the design is complete and in the implementation phase, engineers can observe its functionality. They can change materials to improve performance or appearance as part of revisions. Engineers may also make changes to the design if requested by their superiors or clients. Modifications may also be necessary if the scope of the project or the budget experiences significant alteration.

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