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.
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
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...
THAT’S IT FOR TODAY!
...