3D drawings (isometric, perspective) * Exploded-view 3D drawings * Complete working drawings * Detail drawings (2D orthogonal projections) * Diagrams are a type of technical drawing that uses looser, less uniform rules. They are useful for showing relationships between elements without obscuring the view with too much detail.
Technical drawings might be two-dimensional (orthogonal) plans, sections, and elevations or three-dimensional or exploded projections. They can be hand-drawn to scale or created with computer-aided design (CAD) software. Technical drawings contain all the information necessary for the person who wants to construct or repair an object using their knowledge of engineering and construction practices. The word "technical" is used because people not trained in engineering could still understand them by knowing what things look like and how they are put together.
A technical drawing usually contains the following elements:
Elements specific to plan view drawings include axes and coordinates, which show where to make cuts if needed to separate one part of the drawing from another. Other common elements include scales and symbols that represent objects such as doors, windows, and walls. Dimensions between selected points on these objects indicate sizes such as width, height, and length. Angles are commonly shown with radiating lines or arrows. Certificates of conformance indicate materials used in construction, while tolerances provide information about acceptable variations in dimensions. Drawings also may include notes written by the drafter explaining his or her methods and procedures for creating the illustration.
The key to successful representation of mechanical parts is accurate and clear drawing of detail.
Technical drawing sets Working drawings are a set of technical drawings utilized throughout the product's production phase. Civil drawings, architectural drawings, structural drawings, mechanical system drawings, electrical drawings, and plumbing drawings are examples of architectural drawings. A common set of civil drawings is used by a project manager to identify issues with a site before they start construction. These issues include size and location of structures, property lines, utilities, etc.
The civil engineer uses these drawings to determine how to best position buildings and other structures within a site, as well as where to locate utilities such as water, gas, and electric power lines. The structural engineer uses the drawings to determine how to best frame a building on its site and which materials should be employed in its construction. The interior designer may use the drawings to help determine what kind of finishes should be applied to specific surfaces. The contractor uses the drawings to inform him or her of any changes that need to be made to an existing structure before starting work. For example, if it is discovered that a wall is not straight, has poor load-bearing capacity, or is about to collapse, then it must be repaired or replaced.
Civil engineers use working drawings to identify issues with a site before they start construction.
Perspective drawings, isometric drawings, and oblique drawings are the three basic forms of pictorial drawings that are commonly used in architectural presentations.
In perspective drawings, the viewer's position is related to the subject by means of a third dimension, so that the view appears to come to a point where the lines of sight intersect. Thus, perspective drawings give an accurate representation of three-dimensional objects on a two-dimensional surface. They can also show how objects appear from different angles. Perspective drawings are created using a level as a guide for making horizontal and vertical lines. These marks will help the artist judge how much to shift the viewpoint down or away from its original position.
Isometric drawings show objects with their full dimensions, but they are viewed from a single angle. Thus, isometric drawings present two-dimensional views of three-dimensional objects. Isometric drawings are created by drawing near and far points on either side of a centerline. The centerline should be parallel to the axis of symmetry for accuracy. Distances between objects can be estimated by counting centerlines until they reach a junction point where more than one path leads away from it. Then go along each path and estimate the distances to all other junctions points.
The many forms of construction drawings are shown below.
Pictorial drawings can be isometric, oblique, axonometric, or planometric, and the four drawings in figures 164-167 demonstrate the contrasts between them. Isometric drawings are the most prevalent of them. They show a three-dimensional object from one angle only, usually from above or below it. Thus, isometric drawings can reveal overall relationships among parts of the object being sketched but cannot show detailed features.
Oblique drawings show objects from an angle other than 90 degrees. Thus, they reveal more detail than isometric drawings but not as much as full-size models do. Axonometric drawings show angles equivalent to those of a full-size model; thus, they reveal the most detail of all the sketching techniques but cannot show relationships among parts of the object being sketched. Planometric drawings show angles and dimensions on separate sheets of paper attached to each other with pins or tape; thus, they can show both overall relationships and detailed features of the subject.
In figure 164, the isometric sketch shows the head and neck region of a model with clarity but lacks detail. The oblique sketch shows more detail but does not give us an accurate impression of the shape of the head. The axonometric shows even more detail but does not reveal the relationship of any two specific features on the head (for example, the position of the eyes relative to each other).
Architectural drawings are created using a set of drawing standards that include elevations, sections, cross sections, site plans, and floor plans, among other things. Nowadays, CAD tools like as Revit, AutoCAD, and ArchiCad are used to make the bulk of drawings. Drawing Styles: Drawings for Engineering Projects.
During the planning stage of a project, an architect will create a series of drawings to show how the building or structure will look when complete. After approval of these preliminary designs, the architect will refine the drawings to ensure that they accurately reflect the intended design. The final product is called a detail drawing. At this point, the architect may also produce drawings to indicate specific materials used in the construction, such as steel or wood, and their appropriate methods of installation. These drawings are known as specification drawings.
Detail drawings should include information about the size and location of all materials and elements used on the building's exterior, as well as any special details. For example, a detail drawing might show the exact size of windows and doors, the location of air conditioning units, and any other items used on the exterior of the building. Detail drawings often include notes regarding any changes from the original proposal or contract documents. For example, an architect might note adjustments made to meet local building codes after receiving approval from the building official.
Finally, some projects require drawings showing different views or angles of the building.