How to Read 3D CAD Drawings

CAD, or computer-aided design, has become an increasingly powerful tool for architects, engineers and designers. As traditional pencil and protractor methods have gradually been replaced by powerful digital formats, even consumers and consultants have come into contact with CAD files, and being able to read them has become a very useful skill. Fortunately, most CAD programs generate designs that the average user can interpret with basic computer skills. Being able to read a 3D CAD drawing will not only enable you to understand the mechanics of a design, but will also provide information about other factors such as materials, dimensions and tolerances.

CAD Reader

• 1

  Identify the format of your CAD file. Several CAD programs exist, and their file formats are not always compatible. Thus, you will need to identify what program generated your CAD file by reading the file suffix attached to the file. The file "building.dwg," for instance, is a DWG file.

• 2

  Download the corresponding CAD reader for your file format. While CAD programs can be very expensive, almost all developers provide a free application for reading their files, allowing designers to easily share their designs with coworkers and clients that do not necessarily have the same program. If you are not familiar with the file format, a simple Internet search for the file format and the word "reader" should direct you to the necessary application.

• 3

  Open your 3D CAD file with the corresponding 3D CAD reader. You should now see the design on your screen, along with related information.

Interpreting the Design

• 1

  Identify the different materials used. Most 3D CAD programs have simulated material skins, so if the design calls for concrete or wood, the 3D drawing should have simulated concrete or wood surfaces. For more information, however, such as the exact type of wood used, click on a surface to draw up information on that section. Some CAD programs even have dedicated "materials" screens where you can view the design with information about all the materials used.

• 2

  Read the dimensions of the design. CAD programs have different conventions for scaling, but all programs should include a scale and a ruler for easily measuring a surface and being able to determine the real-world dimensions of a design by multiplying the design surface by the scale factor.

• 3

  Determine the tolerances of each surface and component. For engineering designs, CAD programs include information on tolerances, such as necessary safety distances or structural parameters. This information should appear when you click on a surface or critical point, and understanding these instructions is vital to visualizing the construction of the design. Your design may also include notes with this information; be sure to click on and read all notes in the design.

• 4

  Change views to see the design from different angles. All CAD programs will allow you to rotate the image and view it from different angles, either by manually rotating or setting different view points.