What Is A Projection Drawing In Architecture

Foundations of Drawing I

Elements of Graphic Project

Kyle Steinfeld

This document presents fundamental topics in the mechanics of architectural drawing in the context of graphic projection in general, and of orthographic project in particular.

Our initial give-and-take will remain quite broad, and volition dwell in topics that pertain to projective geometry in full general, as understood past a range of disciplines from engineering, figurer science, and the visual arts. Nosotros will address graphic projection in the service of architectural drawing in particular at a afterwards time.

Starting time, nosotros present the basic elements of graphic projection. Hither, some videos are shown that demonstrate the basic parts of graphic projection drawing: Epitome Plane / Describe Airplane, Projection Rays, Station Signal / View Direction. And so, nosotros present an ontology of projection systems, distinguishing between Parallel vs Perspective Projections, and among Parallel Projections: Orthographic Views, Axons and Obliques.

Architectural drawing

is equally old as

Architecture itself

Past some accounts, it was the formalization of architectural drawings that established architecture as a discipline distinct from the building trades.

Graphic projection is the translation of 3d to 2nd. It offers protocols by which images of three-dimensional objects are projected onto planar surfaces.

For this reason, since iii-dimensional buildings are typically conceived of via ii-dimensional media, architectural drawing has relied heavily on techniques of graphical projection for near of its history. Some form of graphical projection (typically parallel project, orthographic projection, or perspectival project) - either performed past hand or automatically generated with the aid of a estimator - are employed on the vast bulk of architectural drawings.

This text draws a stardom between techniques in graphic projection in full general and architectural cartoon in particular. While technical architectural drawing can trace its roots dorsum to the early renaissance, and is intimately intertwined with advances in geometry and mathematics, projective geometry goes dorsum much further: at least as far as Euclid in the 4th century Advertising.

(left) The Desargues Configuration
(correct) Section of Nest We Grow
Kengo Kuma & Associates with UC Berkeley

Elements of Graphic Projection

Here nosotros briefly describe the elements of graphic projection, and annotation how they are expressed in the 4 most prevalent drawing types in architectural practice.

While some of the terms presented here are used casually in practice, understanding the precise definitions can draw some helpful distinctions.

There are 5 master elements at work in graphic projection:

1. An object to stand for that presents a set up of identifiable features.

2. A plane that receives projections of this object.

3. A set of rays that connect features on the object to positions on the depict plane.

4. A viewer of the draw airplane, sometimes called a 'station point'

5. A ready of cartoon conventions by which the projected locations are re-continued to form an image.

The five elements of graphic projection are: an object, a plane, a set of rays, a viewer, and a fix of drawing conventions.

Let'south examine each of these, one-by-1.

An Object

The object depicted in a graphic projection typically exhibits hands identifiable features

Some objects, such as building-like forms, offer hands identifiable features. Others, such every bit bodies, exercise not.

Some objects, such as buildings, bridges, and machines, offer easily identifiable features. Others, such as bodies, do non. As a engineering science that was created for a specific purpose (cartoon objects made by people), graphic projection is capable of handling some objects with ease, while it struggles with others.

A Plane

The depict plane is the imaginary airplane onto which the cartoon is inscribed

Alternatively referred to as the "draw airplane", "image aeroplane" or in some cases "section aeroplane", this is the imaginary aeroplane onto which the drawing is inscribed. This plane may exist positioned in a number of orientations outside of the object in question, and may also intersect it.

The location and orientation of the draw aeroplane relative to the object depicted has a big effect on the nature of the drawing produced.

The position and relative orientation of the depict airplane is a major factor in differentiating 1 blazon of graphic projection cartoon from another.

A Set up of Rays

Rays that connect certain features of the object in question with positions on the draw plane. Projecting with parallel vs converging rays holds significant implications for the nature of the resulting cartoon. Different kinds of graphic projections may be differentiated by the relationship of these rays to one another and to the draw aeroplane.

A Viewer

An indication of the position of the viewer, indicated in parallel projections simply by a side of the depict plane, and in perspective projections by a indicate in infinite.

The nature of the viewer holds meaning implications for the nature of the resulting cartoon.

In parallel projection drawings, the distance from object to airplane and the distance from aeroplane to viewer does not impact the outcome.

The side from which the plane is viewed, notwithstanding, can impact the outcome.

In perspective projection drawings, in which lines of projection converge, the distance from object to plane and from plane to viewer, do agree a pregnant influence on the resulting cartoon.

A Prepare of Drawing Conventions

Once a prepare of positions has been projected from 3d to 2d, we are left with just this: a set up of locations. To move from these points to a set up of lines that effectively creates an illusion of 3-dimensional infinite and form, we rely on a timeworn set of graphic conventions that dictate the configuration and nature of these lines.

(left) Central California History Museum
Perry Kulper ~2001
(right) Diagram for Courtscraper
Bjarke Ingels ~2015

Conventions by which decisions are fabricated equally to how to depict (or 'render') a set of projected locations equally a drawing are every bit varied as the bailiwick of architecture itself.

Traditionally, projected locations are connected using blackness lines of varying width and way (as described below), as the ways by which architectural drawings could be produced and reproduced were quite limited in terms of tone, colour, and the number of positions plotted. Even within the constraints of these limitations, a remarkable jiff of graphic expression may exist achieved.

A Catalog of Cartoon Types

I made a serial of YouTube videos that explain orthographic project, axonometric and oblique project and perpsective project

Parallel vs Perspective Projections

Parallel Project (left) and Perspective Projection (correct)

The simplest distinction to exist made amongst the four basic systems of graphic projection concerns the relationship amongst the projection rays.

Perspective projections

Projection rays are converge at a "station point" representing the disembodied centre of a viewer. Includes 1, two, 3, and 4 signal perspectives.

Parallel projections

Projection rays are parallel to ane some other. Includes orthographic drawings, axonometrics, and obliques.

Distinctions Amid Parallel Projections

Axonometric Projection (left) and Oblique Projection (correct)

Axonometric projections

Projection rays are parallel to 1 another, and perpendicular to the image plane - but in no specific human relationship to any ascendant airplane of the object depicted.

Oblique projections

Projection rays are parallel to ane another - only non-parallel with the image plane and in no specific relationship to any dominant plane of the object depicted.

Stardom Between Axonometric and Orthographic

Axonometric Projection (left) and Orthographic Project (right)

Axonometric projections

Projection rays are parallel to one another, and perpendicular to the image plane.

Orthographic projections

A special case of axonometric projection in which the epitome plane is parallel with a dominant plane of the object depicted.

Summary of Project Systems

• In Perspective Projections, rays converge at a "station bespeak".

• In Parallel Projections, rays are parallel to i some other. This includes all types listed beneath.

• In Perspective Projections, rays converge at a "station indicate".
• In Parallel Projections, rays are parallel to one another. This includes all types listed below.

  • In Axonometric Projection (a special case of parallel projection), rays are parallel to one another and perpendicular to the image aeroplane.

  • In Oblique Projections, rays are parallel to ane another only are not perpendicular to the image plane.

• In Perspective Projections, rays converge at a "station bespeak".
• In Parallel Projections, rays are parallel to one another. This includes all types listed below.

  • In Axonometric Projection (a special example of parallel projection), rays are parallel to one another and perpendicular to the prototype airplane.

    • In Orthographic Projection (a special case of axonometric projection), the paradigm airplane is parallel to a ascendant plane of the object depicted.

  • In Oblique Projections, rays are parallel to i another just are non perpendicular to the epitome airplane.

Source: http://blah.ksteinfe.com/foundations_of_drawing/drawing_orthographics.html

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