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CHAPTER 1
Guidelines for Drafting
1.1 Introduction
Drafting is the process of creating technical drawings consisting of two-dimensional (2D) images and annotations, and the term draughting is used to describe the language of drafting in this book. Draughting defines the terminology, symbology, conventions, and standards used in drafting. It is the universal technical language that is used for clearly and accurately describing the form, size, finish, and color of a graphic design model for construction or recording. Draughting guidelines deal with standards and conventions in drawing media, lettering, linestyes, projection standards, plot scales, dimensioning rules, sectioning rules, and so on. In this chapter, we will concentrate mainly on drawing media, lettering, and linestyles, while others will be discussed in the appropriate chapters.
The 2D images in drafting are constructed from lines and curves, while annotations are composed from characters. 2D technical drawings may be created using axonometric and perspective principles. Axonometric drawings are 2D drawings obtained by applying orthogonal projection principles to three-dimensional (3D) objects and include orthographic, isometric, dimetric, and trimetric drawings. Pictorial drawings such as isometric and perspective drawings mimic 3D objects in appearance, but are made of 2D entities by composition. Most technical drawings are of the orthographic and isometric types, which are the focus of this book. Some standards and conventions apply to both lines and characters in drafting, and they must be learned and used correctly. Therefore, drafting skills involve learning to correctly apply the rules of draughting in creating acceptable or industry standard technical drawings. Proficiency in drafting involves being able to create high-quality technical drawings, so becoming proficient in drafting must be a commitment executed with determined effort.
1.2 Conventions and Standards
Draughting principles, conventions, rules, and standards help to minimize misinterpretations of drawing contents and eliminate errors in the communication of technical ideas. Conventions are commonly accepted practices, methods, or rules used in technical drawings. Standards are sets of rules established through voluntary agreements that govern the representation of technical drawings. Standards ensure clear communication of technical ideas. The design drafter must study and understand these conventions and standards and learn to apply them correctly in practice. For example, good technical drawings are achieved by following some principles such as:
- Keeping all lines black, crisp, and consistent.
- Using different linestyles.
- Ensuring clarity in linestyle differences such as in thickness or line weight.
- Ensuring dashes have consistent spacing with definite endpoints.
- Keeping guide or construction lines very thin.
- Ensuring that corners are sharp and without overlap in drawing views.
- Placing dimension with thoughtfulness and adequate spacing.
- Making notes simple and concise.
- Making drawing readability a high priority.
- Ensuring a pleasing drawing layout.
Principles one to six are largely built into computer design drafting (CDD) software or packages. This means the CDD operator need not worry about them, except know what linestyle to use for different features of objects and assign appropriate line weight or thickness. However, principles 7 to 10 must be mastered and consistently applied. These have bearings on accuracy, legibility, neatness, and visual pleasantness of drawings.
There are national and international organizations that develop and manage the development of standard...
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