Projection Types
-
Upload
kamran-khan-khalil -
Category
Documents
-
view
221 -
download
0
Transcript of Projection Types
-
7/29/2019 Projection Types
1/20
Types of Projection
-
7/29/2019 Projection Types
2/20
Perspective:When the human eye views ascene, objects in the distance appear smaller
than objects close by - this is knownas perspective. While orthographic projectionignores this effect to allow accuratemeasurements, perspective definition shows
distant objects as smaller to provide additionalrealism.
-
7/29/2019 Projection Types
3/20
-
7/29/2019 Projection Types
4/20
GL2:4
Projection plane
3-D object View point
Projectionrays
2-D projection
Engineering graphics are obtained by projection
from the 3-D object to the viewing surface (the
projection plane)
Perspectiveprojection
-
7/29/2019 Projection Types
5/20
GL2:5
Perspective projection is useful for
non technical communications
Perspective renderings for marketing, etc. are readilyobtained with computer-aided drawing (CAD) systems
-
7/29/2019 Projection Types
6/20
Axonometric: prepared by the projectionof objects on the drawing surface so that
they appear inclined with three sides showingand with horizontal and vertical distancesdrawn to scale but diagonal and curved linesdistorted.
(not to be confused with orthographicprojection) used to create a pictorial drawingof an object, where the object is rotated
along one or more of its axes relative to theplane of projection.
GL2:6
-
7/29/2019 Projection Types
7/20
Orthographic: projection of a single
view of an object (as a view of thefront) onto a drawing surface in whichthe lines of projection are perpendicularto the drawing surface and parallel toeach other.
GL2:7
-
7/29/2019 Projection Types
8/20
Oblique: In both oblique projectionand orthographic projection, parallel lines ofthe source object produce parallel lines in theprojected image. The projectors in obliqueprojection intersect the projection plane at anoblique angle to produce the projected
image, as opposed to the perpendicular angleused in orthographic projection.
GL2:8
-
7/29/2019 Projection Types
9/20
GL2:9
-
7/29/2019 Projection Types
10/20
GL2:10
Bertoline,eta
l.Fig.
9.2
Orthogonal (multiview) Axonometric
Oblique Perspective
-
7/29/2019 Projection Types
11/20
GL2:11
Parallel to
projection plane
Normal to
projection plane
Orthogonal
Inclined to
projection plane
Normal to
projection plane
Axonometric
Parallel to
projection plane
Inclined to
projection plane
Oblique
Orthographic projection(Parallel projectors)
Categories of orthographic projection
Principal
plane of
object
Projectors
-
7/29/2019 Projection Types
12/20
GL2:12
GL2 13
-
7/29/2019 Projection Types
13/20
GL2:13
GL2 14
-
7/29/2019 Projection Types
14/20
GL2:14
GL2 15
-
7/29/2019 Projection Types
15/20
GL2:15
Top horizontal plane
Frontverticalplane
Left profile plane
Third-angle orthogonal projection
Top view
Front view
Leftsideview
Glass projection box
First quadrant
Third quadrant
GL2 16
-
7/29/2019 Projection Types
16/20
GL2:16
Third-angle orthogonal projection
vertical plane
horizontal plane
left profile plane
leftsideview
depth
horizontal plane
verticalplane
leftprofile
plane
depth behindvertical plane
height belowhorizontal plane
top(plan)
view
width
height front
view
depth depth behindvertical plane
O th hi P j ti
-
7/29/2019 Projection Types
17/20
Orthographic Projection:
Isometric Sketches from
Orthographic Views
Sometimes you are asked to constructIsometric sketches from Orthographic viewsto develop visualization skills.
The box method is one way to do this.
For some problems, the box method maynot be very helpful.
-
7/29/2019 Projection Types
18/20
Orthographic Projection:
Isometric Sketches from Orthographic
Views1. Find the object's overall dimensions from the
orthographic views and sketch that size boxon isometric dot paper.
D
H
W
Orthographic Projection:
-
7/29/2019 Projection Types
19/20
Orthographic Projection:
Isometric Sketches from Orthographic
Views
2. Sketch the top, front, and right side views intheir appropriate locations on the box.
Orthographic Projection:
-
7/29/2019 Projection Types
20/20
Orthographic Projection:
Isometric Sketches from
Orthographic Views
3. Add/remove lines until the view is complete.