Orthographic Drawing

Multiview Projection

• Projection a view of an object• Is a photograph enough to describe

an object?• A number of views, systematically

arranged...

Perspective Projection

Source, at a definite distance.

Orthographic Drawing

Source, at an infinite

distance

Four Types of Projection

TOP

BOTTOM

FRONT

LEFT RIGHT

REAR

Six Standard Views

Six Standard Views

Six Standard Views

Orthographic Drawing

Orthographic Drawing

Orthographic Drawing

Unfolding the Glass Box

The Glass Box

Top & Right Side Views

Third Angle Projection

Mitter Line

D/2D/2

D/2 D/2

A transparent picture plane is set up between object and the station point of an observer’s

eye.

T

F R

Third Angle Projection

Mitter line can only be used when the views are placed equidistantl

y.

?????

First Angle Projection (Europe & Asia)

Mitter Line

D/2

D/2

D/2 D/2

The observer looks through the object to the planes of projection.

T

FR

Views of Surfaces

• To effectively create and interpret multiview projections, you have to consider the elements that make up most solids:

SURFACES bounded by straight lines, or curves.

Edge View

True View

Foreshortened View

Normal SurfaceParallel to the

plane of projection (true

shape&size)

Inclined Surface

Perpendicular to a

plane, but inclined or tipped to adjacent planes.

Edge vien on perp. Plane, fs view on inclined planes

Oblique Surface

Tipped to all planes.

FS on all planes.

Normal Edge

True length in adjacent planes

Point on perpendicular

Plane.

Inclined Edge

True length in parallel plane

(angled)

Shortened on adjacent planes

(vertical / horizontal)

Oblique Edge

Shortened &

Angled

Shortened & Angled

Angles

Vertices

•A corner or point, intersection of 3 planes

Meaning of a Point

•A vertex•Point view of an edge

Meaning of a Line

Visible or hidden:•An edge (intersection between 2 surfaces)•Edge view of a surface•Limiting element of a curved surface

Hidden Lines

Dashed hidden lines are used to represent features that would be hidden behind other surfaces.

Center Lines

Used to indicate symmetrical axes of circles

Order of Drawing

•Block out the views•Locate centerlines•Start details and arcs first•Draw dominant details•Check your views

Now : Guess the object....

So the Quiz Object....

Guess the object....

The object .... Is a rectangular prism

Guess the object....

The object ... Is a cylindrical prism

Third Angle Projection...

So The Object...

THAT’S IT FOR TODAY!

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