lecture 2 2 d transformation and projection multi view drawing n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Lecture 2: 2-D Transformation and Projection Multi-view Drawing PowerPoint Presentation
Download Presentation
Lecture 2: 2-D Transformation and Projection Multi-view Drawing

Loading in 2 Seconds...

play fullscreen
1 / 32

Lecture 2: 2-D Transformation and Projection Multi-view Drawing - PowerPoint PPT Presentation


  • 209 Views
  • Uploaded on

Lecture 2: 2-D Transformation and Projection Multi-view Drawing. Outline. Projection Theory Multi-view Projection Principle views & View placement Projection angle Detail drawing: 1view, 2 view, 3 view drawing Creating multi-view drawing View Selection. Projection Theory.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Lecture 2: 2-D Transformation and Projection Multi-view Drawing' - sharon-dennis


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
lecture 2 2 d transformation and projection multi view drawing

Lecture 2:2-D Transformation and ProjectionMulti-view Drawing

PTT 105/3 Engineering Graphicss

outline
Outline
  • Projection Theory
  • Multi-view Projection
  • Principle views & View placement
  • Projection angle
  • Detail drawing: 1view, 2 view, 3 view drawing
  • Creating multi-view drawing
  • View Selection

PTT 105/3 Engineering Graphicss

projection theory
Projection Theory
  • Engineering and technical graphics are depend on projection methods.
  • Two methods commonly used:
    • Parallel: object positioned at infinity& viewed from multiple points on an imaginary line, parallel to the object.
    • Perspective: object positioned atfinite distance & viewed from a single point.

PTT 105/3 Engineering Graphicss

slide4

Projection theory comprises of principles used to graphically represent 3D objects on 2D media based on 2 variables:

    • Line of Sight (LOS): an imaginary ray of light between an observer’s eye and an object.
      • Parallel- all LOS are parallel
      • Perspective- all LOS start at a point.
    • Plane of projection: an imaginary flat plane where the image created by LOS is projected.

PTT 105/3 Engineering Graphicss

orthographic projection
Orthographic Projection
  • A parallel projection technique
    • The projection plane is placed between observer and object.
    • The projection plane is also perpendicular to the parallel line of sight.

PTT 105/3 Engineering Graphicss

multi view projection
Multi-view projection
  • Multi-view projection is an orthographic projection for which the object is behind the plane of projection.

PTT 105/3 Engineering Graphicss

slide7

Multi-view drawings

i. Employ multi-view projection technique

ii. Generally 3 views of an object are drawn

iii. Each view is a 2D flat image

PTT 105/3 Engineering Graphicss

example multi view projection
Example: Multi-view Projection

PTT 105/3 Engineering Graphicss

multi view lines
Multi-view Lines

PTT 105/3 Engineering Graphicss

multi view planes
Multi-view: Planes

PTT 105/3 Engineering Graphicss

multi view planes1
Multi-view: Planes

PTT 105/3 Engineering Graphicss

multi view 6 principle views
Multi-view: 6 Principle Views
  • The 6 principle views are the sixmutually perpendicular views that are produced by six perpendicular planes of projection.
  • Image an object is suspended in a glass box, the 6 sides become projection plane showing the six views.

PTT 105/3 Engineering Graphicss

slide13

The views are laid flat by “unfolding the glass box”

  • This forms the basis of two important multi-view drawing standard:
    • Alignment of views
    • Fold lines
  • Top and bottom views are all aligned vertically & share the same height with dim.
  • Rear, left, front and right side are aligned horizontally & share same height with dim.

PTT 105/3 Engineering Graphicss

slide14

Fold lines are imaginary hinged edges of the glass box

i. The fold line between the top & front views is labeled H/F

ii. The distance from a point in front view to the H/F is the same as the distance from the corresponding point in the top view to the H/F fold line.

PTT 105/3 Engineering Graphicss

view placement
View Placement

PTT 105/3 Engineering Graphicss

view placement1
View Placement

The arrangement of views may vary as shown, where the top view is considered the central view.

PTT 105/3 Engineering Graphicss

angle projection
Angle Projection
  • There are two standard arrangement of all six views of an object

i. First-angle projection

ii. Third-angle projection

  • Each uses different symbol
  • The names are derived from the method used to view the object being drawn

PTT 105/3 Engineering Graphicss

slide18

In 1st angle projection, the object is placed

in the first quadrant.

  • In 3rd angle projection, the object is placed in third quadrant.

PTT 105/3 Engineering Graphicss

slide19

Rules:

  • Symbols

(a) 1st angle projection (b) 3rd angle projection

PTT 105/3 Engineering Graphicss

example 1 st and 3 rd angle view projection
Example: 1st and 3rd angle view projection

PTT 105/3 Engineering Graphicss

1 2 and 3 view drawing
1, 2 and 3 view drawing

PTT 105/3 Engineering Graphicss

step in creating multi view drawing
Step in creating multi-view drawing

PTT 105/3 Engineering Graphicss

creating 3 view drawing
Creating 3-view drawing
  • Draw border/frame, title block, etc.
    • Draw border, title block
    • Locating the view

i. should be approx. in

centre

ii. distance between view

= total length available

– view length / 3

    • Drawing projection lines

PTT 105/3 Engineering Graphicss

creating 3 view drawing1
Creating 3-view drawing

2. Light construction of the

views

  • Draw light/thin horizontal & vertical lines accordingly for front view
  • Draw center lines and hidden lines as final
  • Draw top (or side) view
  • Project top view (or side) from front view using thin, light construction line
  • Draw side (or top) view
  • Project side view (or top) from front view and top (or side) view
  • All arcs and circles should be lined (final) at this stage

PTT 105/3 Engineering Graphicss

creating 3 view drawing2
Creating 3-view drawing

PTT 105/3 Engineering Graphicss

creating 3 view drawing3
Creating 3-view drawing

3. Lining in of the views

  • To darken all visible edges (lines that represent a hard edge)
  • Done using thick, black pencil (0.5mm, 2B)
  • Should be done systematically for 3 views
  • Start with horizontal line at the top of the top/plan view, working down the page using T-square
  • From left hand side, working across the page, line in all vertical lines, using T-square and set square
  • Projection lines may be left on the drawing if they are light

PTT 105/3 Engineering Graphicss

creating 3 view drawing4
Creating 3-view drawing

4. Write dimensioning, notes, annotation, etc.

  • Be aware of redundant dimensioning

5. Complete drawing by writing the rest of title block, parts list & revision table, and others

PTT 105/3 Engineering Graphicss

view selection
View Selection

4 basic decisions:

1. Determine the best position. The objectmust bepositioned such a way that the surface of major features are either perpendicular or parallel to glass planes

PTT 105/3 Engineering Graphicss

view selection1
View Selection

2. Define the front view. Should show the

object in natural state and show most features

PTT 105/3 Engineering Graphicss

view selection2
View Selection
  • Determine the minimum number of views needed to completely describe the object.

PTT 105/3 Engineering Graphicss

view selection3
View Selection

4. Determine other views that fewest number of hidden lines

PTT 105/3 Engineering Graphicss

slide32

THANK YOU…

PTT 105/3 Engineering Graphicss