Plans are a set of drawings or two-dimensional diagrams used to describe a place or object, or to communicate building or fabrication instructions. Usually plans are drawn or printed on paper, but they can take the form of a digital file.
The term "plan" may casually be used to refer to a single view, sheet, or drawing in a set of plans. More specifically a plan view is an orthographic projection looking down on the object, such as in a floor plan.
Overview
Plans are often for technical purposes such as architecture, engineering, or planning. Their purpose in these disciplines is to accurately and unambiguously capture all the geometric features of a site, building, product or component. Plans can also be for presentation or orientation purposes, and are often less detailed versions of the former. The end goal of plans is either to portray an existing place or object, or to convey enough information to allow a builder or manufacturer to realize a design.
Plans are often prepared in a "set". The set includes all the information required for the purpose of the set, and may exclude views or projections which are unnecessary. A set of plans can be on standard office-sized paper or on large sheets. It can be stapled, folded or rolled as required. A set of plans can also take the form of a digital file in a proprietary format such as DWG or an exchange file format such as DXF or PDF.
Plans are often referred to as "blueprints" or "bluelines". However, the terms are rapidly becoming an anachronism, since these copying methods have mostly been superseded by reproduction processes that yield black or multicolour lines on white paper, or by electronic representations of information.
Plans are usually "scale drawings", meaning that the plans are drawn at a specific ratio relative to the actual size of the place or object. Various scales may be used for different drawings in a set. For example, a floor plan may be drawn at 1:48 (or 1/4"=1'-0") whereas a detailed view may be drawn at 1:24 (or 1/2"=1'-0"). Site plans are often drawn at 1" = 20' (1:240) or 1" = 30' (1:360).
In the metric system the ratios commonly are 1:5, 1:10, 1:20, 1:50, 1:100, 1:200, 1:500, 1:1000, 1:2000 and 1:5000
Views and projections
Symbols used to define whether a projection is either Third Angle (right) or First Angle (left)Comparison of several types of graphical projection
Because plans represent three-dimensional objects on a two-dimensional plane, the use of views or projections is crucial to the legibility of plans. Each projection is achieved by assuming a vantage point from which to see the place or object, and a type of projection. These projection types are:
Classification of Plan (drawing) and some 3D projections
There is no universal standard for sheet order, however the following describes a common approach:
General Information: The first sheets in a set may include notes, assembly descriptions, a rendering of the project, or simply the project title.
Site: Site plans, including a key plan, appear before other plans and on smaller projects may be on the first sheet. A project could require a landscape plan, although this can be integrated with the site plan if the drawing remains clear.
Specific plans: Floor plans, starting with the lowest floor and ending with the roof plan usually appear near the beginning of the set. Further, for example, reflected Ceiling Plans (RCP)s showing ceiling layouts appear after the floor plans.
Elevations: Starting with the principal, or front elevation, all the building elevations appear after the plans. Smaller residential projects may display the elevations before the plans. Elevation details may appear on the same sheets as the building elevations.
Sections: Building sections that describe views cut through the entire building appear next, followed by wall sections, then detail sections.
Details: Details may appear on any of the previous sheets, or may be collected to appear on detail sheets. These details may include construction details that show how the components of the building fit together. These details may also include millwork drawings or other interior details.
Schedules: Many aspects of a building must be listed as schedules on larger projects. These include schedules for windows, doors, wall or floor finishes, hardware, landscaping elements, rooms, and areas.
Where additional systems are complex and require many details for installation, specialized additional plan drawings may be used, such as:
Structural: While smaller projects may only show structural information on the plans and sections, larger projects have separate sheets describing the structure of the building.
Electrical :Electrical plan drawings may include equipment and cable tray layout, lighting and power, grounding, telephone, local area network, special communications or signal systems, or a reflected lighting plan.
Technical drawing, drafting or drawing, is the act and discipline of composing drawings that visually communicate how something functions or is constructed.
Isometric projection is a method for visually representing three-dimensional objects in two dimensions in technical and engineering drawings. It is an axonometric projection in which the three coordinate axes appear equally foreshortened and the angle between any two of them is 120 degrees.
An engineering drawing is a type of technical drawing that is used to convey information about an object. A common use is to specify the geometry necessary for the construction of a component and is called a detail drawing. Usually, a number of drawings are necessary to completely specify even a simple component. These drawings are linked together by a "master drawing." This "master drawing" is more commonly known as an assembly drawing. The assembly drawing gives the drawing numbers of the subsequent detailed components, quantities required, construction materials and possibly 3D images that can be used to locate individual items. Although mostly consisting of pictographic representations, abbreviations and symbols are used for brevity and additional textual explanations may also be provided to convey the necessary information.
Orthographic projection is a means of representing three-dimensional objects in two dimensions. Orthographic projection is a form of parallel projection in which all the projection lines are orthogonal to the projection plane, resulting in every plane of the scene appearing in affine transformation on the viewing surface. The obverse of an orthographic projection is an oblique projection, which is a parallel projection in which the projection lines are not orthogonal to the projection plane.
A 3D projection is a design technique used to display a three-dimensional (3D) object on a two-dimensional (2D) surface. These projections rely on visual perspective and aspect analysis to project a complex object for viewing capability on a simpler plane.
Axonometric projection is a type of orthographic projection used for creating a pictorial drawing of an object, where the object is rotated around one or more of its axes to reveal multiple sides.
Descriptive geometry is the branch of geometry which allows the representation of three-dimensional objects in two dimensions by using a specific set of procedures. The resulting techniques are important for engineering, architecture, design and in art. The theoretical basis for descriptive geometry is provided by planar geometric projections. The earliest known publication on the technique was "Underweysung der Messung mit dem Zirckel und Richtscheyt", published in Linien, Nuremberg: 1525, by Albrecht Dürer. Italian architect Guarino Guarini was also a pioneer of projective and descriptive geometry, as is clear from his Placita Philosophica (1665), Euclides Adauctus (1671) and Architettura Civile, anticipating the work of Gaspard Monge (1746–1818), who is usually credited with the invention of descriptive geometry. Gaspard Monge is usually considered the "father of descriptive geometry" due to his developments in geometric problem solving. His first discoveries were in 1765 while he was working as a draftsman for military fortifications, although his findings were published later on.
Oblique projection is a simple type of technical drawing of graphical projection used for producing two-dimensional (2D) images of three-dimensional (3D) objects.
In architecture and building engineering, a floor plan is a technical drawing to scale, showing a view from above, of the relationships between rooms, spaces, traffic patterns, and other physical features at one level of a structure.
In three-dimensional geometry, a parallel projection is a projection of an object in three-dimensional space onto a fixed plane, known as the projection plane or image plane, where the rays, known as lines of sight or projection lines, are parallel to each other. It is a basic tool in descriptive geometry. The projection is called orthographic if the rays are perpendicular (orthogonal) to the image plane, and oblique or skew if they are not.
CAD Standards are a set of guidelines for the way Computer-aided drafting (CAD), or (CADD) Computer Aided Design and Drawing, drawings should appear, to improve productivity and interchange of CAD documents between different offices and CAD programs, especially in architecture and engineering.
An exploded-view drawing is a diagram, picture, schematic or technical drawing of an object, that shows the relationship or order of assembly of various parts.
A house plan is a set of construction or working drawings that define all the construction specifications of a residential house such as the dimensions, materials, layouts, installation methods and techniques.
A drafter is an engineering technician who makes detailed technical drawings or plans for machinery, buildings, electronics, infrastructure, sections, etc. Drafters use computer software and manual sketches to convert the designs, plans, and layouts of engineers and architects into a set of technical drawings. Drafters operate as the supporting developers and sketch engineering designs and drawings from preliminary design concepts.
In technical drawing and computer graphics, a multiview projection is a technique of illustration by which a standardized series of orthographic two-dimensional pictures are constructed to represent the form of a three-dimensional object. Up to six pictures of an object are produced, with each projection plane parallel to one of the coordinate axes of the object. The views are positioned relative to each other according to either of two schemes: first-angle or third-angle projection. In each, the appearances of views may be thought of as being projected onto planes that form a six-sided box around the object. Although six different sides can be drawn, usually three views of a drawing give enough information to make a three-dimensional object.
An architectural drawing or architect's drawing is a technical drawing of a building that falls within the definition of architecture. Architectural drawings are used by architects and others for a number of purposes: to develop a design idea into a coherent proposal, to communicate ideas and concepts, to convince clients of the merits of a design, to assist a building contractor to construct it based on design intent, as a record of the design and planned development, or to make a record of a building that already exists.
Construction surveying or building surveying is to provide dimensional control for all stages of construction work, including the stake out of reference points and markers that will guide the construction of new structures such as roads, rail, or buildings. These markers are usually staked out according to a suitable coordinate system selected for the project.
A structural drawing, a type of engineering drawing, is a plan or set of plans and details for how a building or other structure will be built. Structural drawings are generally prepared by registered professional engineers, and based on information provided by architectural drawings. The structural drawings are primarily concerned with the load-carrying members of a structure. They outline the size and types of materials to be used, as well as the general demands for connections. They do not address architectural details like surface finishes, partition walls, or mechanical systems. The structural drawings communicate the design of the building's structure to the building authority for review. Structural drawings are also included with a proposed building's contract documents, which guide contractors in detailing, fabricating, and installing parts of the structure.
Mechanical systems drawing is a type of technical drawing that shows information about heating, ventilating, air conditioning and transportation around the building. It is a powerful tool that helps analyze complex systems. These drawings are often a set of detailed drawings used for construction projects; it is a requirement for all HVAC work. They are based on the floor and reflected ceiling plans of the architect. After the mechanical drawings are complete, they become part of the construction drawings, which is then used to apply for a building permit. They are also used to determine the price of the project.
Peter Jeffrey Booker was a British engineer and technological drawing historian, known for his 1963 A history of engineering drawing, a seminal work on the history of technical drawing.
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