projection dwgs

8/2/2019 Projection Dwgs

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ARCHITECTURAL

GRAPHICSTypes of Projection Drawings, Classifications & Definitions:

Prepared by: R Chenoweth

Sources:

Architectural Drawing Patten and RognessThird Edition, 1969

Google images


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Projection Drawings Types

Orthographic

Oblique

Perspective


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Orthographic: Multi-View

Plans, Elevations, Sections

All sides of the form are parallel to the

drawing surface.

This means the drawings are represented

without distortion or foreshortening.


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Orthographic: Multi-view

The primarydrawings used

in Architectureare Multi-view:

Plans

Sections Elevation


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Orthographic:

Axonometric

3 types Three faces of a rectangular object

are shown in one drawing.

Trimetric All axes make different angles with

picture plane

Dimetric

Two axes make equal angles withpicture plane

Isometric The three axes make equal angles

with picture plane


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Oblique Projection

Three faces of a rectangular object are shown

in one drawing. The front face of the object is the same as the

front picture plane of a multi-view orthographic.

Most practical when intricate detail or contour

appear in the front face.


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Oblique Projections

Explodeddrawings often

are Obliquerather thanaxonometric.

This allows for

circles and arcsto be shown

true if they areon the parallel orfront face.


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Oblique:

Cavalier & Cabinet Cavalier Oblique drawing

Used when distortion is acceptable

Each face is drawn at full scale Quickest to draw to scale.

Cabinet Oblique drawing

Most often seen

The front face is drawn at full scale

The side & top are typically at 1/2 scale

Does not show as much side & topdetail as the General


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Oblique: General

General Oblique drawing

Used when distortion is NOT acceptable

The front face is drawn at full scale

The side & top are typically 2/3 or 3/4 scale


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Perspective projections

Perspective is what theeye sees

All three dimensions

(length, width, andheight) become smallerfor the parts of the objectthat are farther from theviewer or camera.

This kind of drawingindicates depth ordistance even with theuse of a simple linear

perspective.


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Perspective:

One-point

A One-point

perspectivemaintains oneface parallel to

the picture plane. One vanishing

point is used.


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Perspective:

Two-point

A Two-point perspective haseach vertical face oblique tothe picture plane.

Two vanishing points are used.


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Perspective:

Three-point A Three-point

perspective

has eachvertical faceoblique to thepicture plane.

Threevanishingpoints areused.

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