Transcript ORTHOGRAPHIC PROJECTION

SANTANA
DRAFTING
MULTIVIEWS 1
An introduction
Mr. Fitzgerald
Rm. 1372
TODAY’S OBJECTIVE…
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Introduce the basic principles of
orthographic projection
Construct an orthographic Multiview of a
simple object
Visualize 3-D objects from multiview
orthographic drawings
TWO TYPES OF DRAWINGS
1.
Orthographic
a)
Multiview
a)
b)
Pictorial
a)
Six Principle Views
b)
c)
d)
e)
f)
Full
Half
Offset
Partial
Revolved
Auxiliary
Auxiliary
a)
b)
c)
d)
Primary
Partial
Secondary
Revolved
Axonometric
a)
Section
a)
c)
1.
b)
c)
b)
Oblique
a)
b)
c)
c)
Isometric
Dimetric
Trimetric
Cavalier
Cabinet
Others
Perspective
a)
b)
c)
One Point
Two Point
Three Point
IT IS A 3-D WORLD
The three dimensions are
1.
2.
3.
Height
Width
Depth
Pairing the dimensions with one another creates
three planes used in orthographic projection
1.
2.
3.
Profile Plane = Height + Width
Horizontal Plane = Width + Depth
Vertical Plane = Height + Depth
ANGLES OF PROJECTION
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First Angle
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Projection Plane is
placed on the other
side of object from
viewer
Object is placed in the
first quadrant
Primarily used in
Europe and Asia
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Third Angle
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Projection Plane is
placed between the
object and the viewer
Object is placed in the
third quadrant
Primarily used the
United States
ORTHOGRAPHIC PROJECTION
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Ortho – Greek word meaning perpendicular
Orthographic literally means perpendicular view
To look straight at an objects hides a dimension
Show the views of a 3-D object projected in 2-D
Most common is the front top and side views
MULTIVIEWS (third angle of projection)
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Picture an object in
the center of a glass
cube
Project the surfaces
onto the faces of the
glass cube
Multiviews:
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Unfold the cube so that it
lies in a single plane
Multiple views of the
object are now visible on
the same plane in space
There are SIX PRINCIPLE VIEWS
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Front, Top, Right, Left, Bottom & Back
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In this class we know which view we are
looking at by it’s relationship to the front
side view – NEVER LABEL YOUR
VIEWS in this class!
There are SIX PRINCIPLE VIEWS
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Although there are six principle views you
only need to draw the ones that are
necessary to define the object
It is common to show three principle views
in this class, front, top & side
MULTIVIEWS:
When the glass cube is unfolded:
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FRONT VIEW: Height and Width (Profile Plane)
TOP VIEW: Width and Depth (Horizontal Plane)
RIGHT SIDE VIEW: Depth and Height (Vertical Plane)
MULTIVIEWS: Align views
with each other (features project
from one view to the next)
POINTS, LINES & SURFACES
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Point – a location in space - often the
intersection of at least two object lines
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When projecting a point to the adjacent view,
it is always on a straight line parallel to the
plane of projection
Such that when projecting a point from the
front side view to the top side view it would
be directly above it
POINTS, LINES & SURFACES
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(Object) Lines – represent the intersection of two surfaces
& are projected by using their endpoints
Four Types of object lines (three are straight)
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Normal – (Horizontal & Vertical) appear true length on two
planes of projection and as a point in the third
Inclined – parallel to one plane of projection (true size) an
inclined to the other two (foreshortened)
Oblique – not parallel, not perpendicular to any plane of
projection (foreshortened in all three planes of projection)
Curved (not straight) – only circles and arcs of circles can be
projected using its endpoints
POINTS, LINES & SURFACES
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Four types of surfaces
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Normal – Given three views, a normal surface will
appear true in size & shape in one and as an edge in the
other two
Inclined –will appear foreshortened in two views & the
edge view will be neither horizontal or vertical
Oblique – will appear foreshortened in all three view
Curved – Cylinders appear as a circle in one view and
as rectangle in the adjacent view
This lesson will focus on normal surfaces
MULTIVIUEWS:
NORMAL SURFACES
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Parallel to one of the three planes of
projection in which it appears true in size
& shape
MULTIVIUEWS:
NORMAL SURFACES
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Parallel to one of the three planes or two panes of
glass in our transparent cube
Show true size and shape in the view they are
parallel to
Shown as edges in other principle views
MULTIVIUEWS:
LINE TYPES
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When two surfaces meet it creates a line
(edge)
When that edge is visible we use an object
line (a clear, crisp & dark solid line)
When that edge is behind a surface (not
visible) we use a hidden line (a clear, crisp
& dark dashed line)
When a hidden line is directly behind an
object line the object line takes precedent
Is the front of the car shown in the front side view?
WhyFront
or why not?
Selecting the
Side View
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Profile View
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Most details
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Best view that shows shape or contour
Fewest hidden lines
Natural or functioning position
Principle Surface area parallel to plane of
projection
Minimize depth
Select an appropriate front side view and begin to hand sketch a
multiview (Front, Top, side) of this part now.
Do not worry about scale but do your best to project (align)
.