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Graphics communication using engineering drawings and models is a language, a clear, precise language with definite rules that must be mastered if you are to be successful in engineering design. Once you know the language of graphics communications, it will influence the way you think, the way you approach problems. Why? Because humans tend to think using the languages they know. Thinking in the language of engineering graphics, you will visualize problems more clearly and will use graphic images to find solutions with greater ease.
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| 1.1 In engineering, 92 percent of the design process is graphically based. The other 8 percent is divided between mathematics, and written and verbal communications. Why? Graphics serves as the primary means of communication for the design process. |
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| 1.2 Drafting and documentation, along with design modeling, comprise over 50 percent of the engineer's time and are purely visual and graphical activities. Engineering analysis depends largely on reading engineering graphics. Manufacturing engineering and functional design also require the production and reading of graphics. |
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| 1.3 Engineering graphics can also communicate solutions to technical problems. Such engineering graphics are produced according to certain standards and conventions so they can be read and accurately interpreted by anyone who has learned those standards and conventions. |
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| 1.4 A designer has to think about the many features of an object that cannot be communicated with verbal descriptions. Technical drawings are a nonverbal method of communicating information. |
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| 1.5 Engineers are creative people who use technical means to solve problems. They design products, systems, devices, and structures to improve our living conditions.Technologists assist engineers and are concerned with the practical aspects of engineering in planning and production. Both engineers and technologists are finding that sharing technical information through graphical means is becoming more important as more non-technical people become involved in the design/manufacturing process. |
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| HUMAN COMMUNICATION SYSTEMS Spoken language and writing are highly refined communications systems that humans use to express emotions, information, and other needs. Mathematics is an abstract, symbol-based communications system built on formal human logic. Graphics is a visual communications language incorporating text, images, and numeric information. |
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| 1.6 Egyptian hieroglyphics were abstract pictures used for communication. |
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| THE IMPORTANCE OF ENGINEERING GRAPHICS Engineering graphics is a real and complete language used in the design process for:
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| 1.7-8 A drawing is a graphical representation of objects and structures and is done using freehand, mechanical, or computer methods. Drawings may be abstract, such as the multiview drawings shown in, or more concrete, such as the very sophisticated computer model shown in. |
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| 1.9 Technical drawing is used to represent complex technical ideas with sufficient precision for the product to be mass-produced and the parts to be easily interchanged. |
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| THE HISTORY OF GRAPHICS COMMUNICATIONS Drawing is so old that its history is virtually that of humanity and it closely parallels human techological progress. |
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| 1.10 Drawings to communicate technical ideas may even pre-date the advent of written language. |
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| 1.11 A timeline showing significant accomplishments in graphics. |
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| 1.12 The earliest evidence of drawing instruments can be found in the Museum of the Louvre, Paris, on two headless statues of Gudea (2130 B.C.). On the knees of the statue, the sculptor modeled two contemporary drawing boards. The drawing boards are inscribed with the plan view of the temple of Ningirsu and with some kind of scribing instrument and scales. |
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The ancient Greeks had a great deal of influence on drawing through their work in geometry. Many of the tools still used in engineering, such as the compass and triangles, were developed at this time. Around the year 450 b.c., a type of perspective drawing was developed by foreshortening and converging parallel lines in their drawings. There was very little development in art and drawing from Christ's time until the Renaissance. |
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| 1.13 da Vinci wrote a treatise on the theory of perspective drawings. |
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| 1.14 Durer used orthographic projection techniques in many of the illustrations. He also developed a method of more easily creating perspective drawings by using a perspective picture window. |
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| 1.15-18 From the 1400s on, the perspective technique has been the primary method used to communicate graphically. However, people have realized that perspective drawings have limitations in presenting true conditions, especially for technical purposes. |
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| 1.19 Gaspard Monge organized and developed the science of technical drawing called descriptive geometry. He used orthographic projection and the revolution method to solve the complicated fortress problems graphically instead of mathematically. Monge developed the science of descriptive geometry in the late 1700s. It is the basis for all types of three-dimensional representations on two-dimensional media used today. |
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VISUAL SCIENCE |
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| 1.20 Visual science is the study of the visual and technical applications of graphics.Visualization is the process of mentally understanding visual information.Geometry is a branch of mathematics that deals with the properties, relationships, and measurements of points, lines, angles, planes, and solids. Visualization ability and a knowledge of geometry combine to create both artistic and technical drawings. |
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| 1.21 Artistic drawings are used to express aestetic, philosophical, and abstract ideas, whiletechnical graphics ortechnical drawing is a specialized type of graphics used to communicate technical information. |
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| 1.22 Plane geometry - the geometry of planar figures, such as circles and triangles, and their relationships. |
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| 1.23 Solid geometry - the geometry of three-dimensional objects, such as cylinders, cubes and spheres, and their relationships. Analytical geometry - the analysis of geometric structures and properties, principally using algebraic operations and position coordinates. Descriptive geometry - the science of analyzing and solving space distances and relationships, using graphics. |
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| 1.24 Conventions are commonly accepted practices, rules, or methods used in technical drawing. |
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| 1.25 Standards are sets of rules that govern how technical drawings are represented. Standards allow for the clear communication of technical ideas. In the United States, theAmerican National Standards Institute (ANSI) is the governing body that sets the standards used for engineering and technical drawings. |
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SPECIALISTS AND TECHNICAL DRAWINGS |
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| 1.26 Mechanical engineering comprises a wide range of activities that include the research, design, development, manufacture, management, and control of engineering systems and their components. Mechanical engineers use a wide variety of mechanical drawings and computer models for design and analysis. Electrical engineering includes the research, design, development, marketing, field testing, and operation and maintenance of electrical and electronic systems and their components. Electrical engineers use schematic drawings and electromechanical drawings of electrical systems for communications. Agricultural engineering includes the technical aspects of production agriculture and its natural resource base, and the processing and chemistry of biological materials for food and industrial products. Agricultural engineers use mechanical drawings of agricultural machinery for design and communication. Civil engineering involves the planning, design, construction, operation, and maintenance of transportation, environmental, and construction systems. Civil engineers use working drawings of construction systems, map drawings, and other detail drawings for communications. Industrial engineering is a broad professional discipline concerned with the analysis and design of systems for organizing basic production resources, such as people, information, materials, and equipment. Industrial engineers must be able to produce and read manufacturing facility drawings and layouts and create computer models for design and analysis. Materials engineering comprises a wide spectrum of activities directed toward the design, development, and production of metals, alloys, ceramics, semiconductors, and other materials for engineering applications. Chemical engineering includes those technical activities in which chemistry and other basic sciences are used to solve problems related to energy, health, the environment, food, clothing, shelter, and materials. Chemical engineers must be able to produce and read drawings and create complex computer models of chemical plants for design and analysis. Aerospace engineering includes the design and operation of many types of aircraft, missiles, and space vehicles. Aerospace engineers must be able to produce and read drawings and computer models of aircraft, missiles, and space vehicles for their design, analysis, and production. |
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| ENGINEERING TECHNOLOGY Theengineering technologist assists the engineer and is concerned with the practical aspects of engineering, in both planning and production. |
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| SUMMARY As a student of engineering graphics, you will study and learn to apply the tools used to create engineering drawings and models. Even more important, you will also learn the underlying principles and concepts of engineering graphics, such as descriptive geometry. You will also learn the standards and conventions that will enable you to create drawings and models that can be read and accurately interpreted by engineers or technologists anywhere. The ability to draw is a powerful skill. It gives a person's thoughts visible form. Engineering drawings can communicate complex ideas both efficiently and effectively, and it takes special training to be able to produce these complex images. If drawings are "windows to our imaginations," then engineering drawings are specialized windows that give expression to the most complex, technical visions our minds can imagine. Engineering drawing does more than communicate. Like any language, it can actually influence how we think. Knowing how to draw allows you to think of and deal with many problems that others may not. Knowledge of technical graphics helps you more easily envision technical problems, as well as their solutions. In short, engineering graphics is a necessity for every engineer and technologist. |