Throughout human history we have used pictures to convey ideas, express ourselves, present information, etc. Basically we have used pictures to communicate. However different people and cultures used different types of pictures to communicate ideas.
This was a problem that faced engineers, designers, builders, architects, etc. throughout history. We didn't have one way of communicating our ideas that everybody understood.
Gaspard Monge faced this problem when he started as an Engineer in the French Military. He devised a system that could be used to communicate an object to anyone across the world. This system is called Orthographic Projection and was quickly adopted by army engineers. However France was at war and Monge's system was kept top secret. It wasn't until many years later that Monge was allowed to publish and teach his system. Shortly this system spread across and revolutionized world industry. (Orthographic Projection.com)
- Perspective drawing technique was invented during the Renaissance period (1300-1500)
- Descriptive geometry was invented by Gaspard Monge in 1765
- Orthographic projection technique was invented during the Industrial Revolution period (1770-1850)
- 2-D CAD systems were developed in the 1980s
- 3-D CAD systems were developed in the 1990s
Perspective drawing technique
Perspective in the graphic arts is an approximate representation of an image, on a flat surface (such as paper). Perspective projection is used to draw the three dimensional picture of an object as it appears to the human eye. Perspective is one of the foundations of realism in art.
The two most characteristic features of perspective are:
- Objects are smaller as their distance from the observer increases.
- Object's dimensions along the line of sight are shorter than its dimensions across the line of sight.
Until artists figured out perspective, there was no accurate system for drawing architecture or other geometric space. Italian Renaissance painters and architects studied linear perspective, wrote treatises on it, and incorporated it into their artworks.
One of the most important innovations in the history of drawing was the development of linear perspective. Linear perspective is based on a series of guidelines and points which help artists create a realistic sense of depth in their drawings. There are several types of linear perspective including one point perspective, two-point perspective, and three point perspective.
At the beginning of the christian era, Roman architects had become skillful in preparing drawing of buildings that were to be constructed. They used straight edges and compasses to lay out the elevation and plan views and were able to prepare well-executed perspectives. However, the theory of projection of views upon imaginary planes of projection was not developed as a means of representation until sometime during the Renaissance period.
Even though it is probable that Leonardo da Vinci was aware of the theory of multiview drawing , his training as an artist prevailed and he recorded his ideas and designs for war machines and mechanical constructions by preparing perspective sketches and drawings. No multiview drawing prepared by da Vinci have been found. He knew the value of a pictorial drawing, and it is interesting to note that even in this day of space travel, we prepare pictorial drawings.
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. Gaspard Monge is usually considered the "father of descriptive geometry". He first developed his techniques to solve geometric problems in 1765 while working as a draftsman for military fortifications, and later published his findings.
Monge's protocols allow an imaginary object to be drawn in such a way that it may be 3-D modeled. All geometric aspects of the imaginary object are accounted for in true size/to-scale and shape, and can be imaged as seen from any position in space. All images are represented on a two-dimensional surface.
Descriptive geometry uses the image-creating technique of imaginary, parallel projectors emanating from an imaginary object and intersecting an imaginary plane of projection at right angles. The cumulative points of intersections create the desired image.
Orthographic projection (or orthogonal projection) is a means of representing a three-dimensional object in two dimensions. It is a form of parallel projection, where 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. It is further divided into multiview orthographic projections and axonometric projections. A lens providing an orthographic projection is known as an (object-space) telecentric lens.
Drafters initially created drawings by hand on a drafting table referred to as a board. An advance in drafting occurred with the introduction of the drafting machine, which replaced the T-square, triangles, scales and protractor for creating drawings.
Computer-aided design (CAD) is the use of computer systems for creation, modification,and analysis of a design.
CAD output is often the electronic files. As in the manual drafting, the output of CAD convey information, such as materials, processes, dimensions, and tolerances.
CAD software for mechanical design uses vector-based graphics to depict the objects of traditional drafting. CAD may be used to design curves and figures in (2D) space; or curves, surfaces, and solids in (3D) space.
CAD was a revolutionary change in the engineering industry, where draftsmen, designers and engineering roles begin to merge; and it empowered draftsman, designers and engineers.
Initially, CAD was typically limited to producing drawings similar to hand-drafted drawings. Current computer-aided design software packages range from 2D vector-based drafting systems to 3D solid and surface modelers. Modern CAD packages can also frequently allow rotations in three dimensions, allowing viewing of a designed object from any desired angle, even from the inside looking out.
The invention of the 3D CAD/CAM is attributed to a French engineer, Pierre Bezier. He developed UNISURF, between 1966 and 1968, to ease the design of parts and tools for the automotive industry. Then, UNISURF became the working base for the following generations of CAD software.
One of the most influential events in the development of CAD was the founding of MCS (Manufacturing and Consulting Services Inc.) in 1971 by Dr. P. J. Hanratty, who wrote the system ADAM (Automated Drafting And Machining).
Key products for 1981 were the Unigraphics solid modelling packages, and the release of the surface modeler CATIA (Dassault Systemes).
Autodesk was founded 1982 by John Walker, which led to the 2D system AutoCAD.
The next milestone was the release of Pro/ENGINEER in 1987, which heralded greater usage of feature-based modeling methods and parametric linking of the parameters of features.
Release of mid-range packages such as SolidWorks in 1995, Solid Edge in 1996 and Autodesk Inventor in 1999.