Multiviews

1
CHAPTER 8

• Multiviews

2
Learning Objectives

• Select appropriate views for presentation
• Prepare single- and multiview drawings
• Create detail views
• Draw view enlargements

3
Learning Objectives

• Establish runouts
• Explain the difference between first- and
  third-angle projection
• Create multiview drawings using first- and
  third-angle projection
• Prepare formal multiview drawings from an
  engineers sketch and actual industry layouts

4
Orthographic Projection

• System for drawing and dimensioning complex
  three-dimensional items
• Changes physical objects and three-dimensional
  ideas into two-dimensional drawings
• Uses descriptive geometry

5
Orthographic Projection

• Lines of sight perpendicular to plane of
  projection
• Surface of the object parallel to the plane of
  projection
• Surface appears true size and shape
• Surface of the object not parallel to the plane
  of projection
• Surface appears foreshortened, or shorter than
  true length
• True geometry view

6
Orthographic Projection
7
Multiviews

• Multiview projection
• Multiview drawing
• The result of multiview projection
• Represents the shape description of the object

8
Multiview Standards

• ASME
• ASME Y14.3, Multi and Sectional View Drawings
• ISO
• Alternate view definition systems

9
The Glass Box Visualization Method

• Sides of the glass box are planes of projection
• Six total sides, or views
• FRONT
• TOP
• RIGHT-SIDE
• LEFT-SIDE
• BOTTOM
• REAR

10
The Glass Box Visualization Method

• Sides unfold at hinge lines, also known as
• Fold lines
• Reference lines

11
The Glass Box Visualization Method

• Arranges views in third-angle projection
• Projection techniques
• 45mitre line
• Arcs
• Transfer

12
Third-Angle Projection

• Primary multiview projection method
• Common in the United States
• Identified by the third-angle projection symbol
• Angle of projection block near the title block

13
First-Angle Projection

• Common in countries other than the United States
• Identified by the first-angle projection symbol
• Angle of projection block near the title block

14
Third-Angle versus First-Angle Projection
15
View Selection

• Six views possible
• FRONT
• TOP
• RIGHT-SIDE
• LEFT-SIDE
• BOTTOM
• REAR

16
View Selection

• Seldom necessary to use all six views
• Only draw the number of views necessary to
  completely described the object
• Front view usually most important
• Establishes other views
• Always one dimension common between adjacent views

17
Selecting the Front View

• Represent the most natural position of use
• Provide the best shape description or most
  characteristic contours
• Have the longest dimension
• Have the fewest hidden features
• Be the most stable and natural position

18
Selecting the Front View
19
Selecting Two or Three Views

• Most contours
• Longest side
• Least hidden features
• Best balance or position

20
Two-View Drawings
21
One-View Drawings

• Thickness identified in a note or title block
• All shape and dimensional information in one view
• If in doubt, drawn the adjacent view

22
Partial Views

• Symmetrical objects drawn in limited space
• Simplify complex views
• Break lines show that a portion of the view is
  omitted

23
Detail View

• Increases the scale of part of a view
• Use when detail cannot be clearly dimensioned due
  to
• Drawing scale
• Complexity

24
Removed Views

• Out of normal arrangement with other views
• Avoid when possible, but may be necessary when
• Limited space
• Enlarge the view
• Can appear on a different sheet from where the
  view is taken if necessary

25
Viewing Plane Lines for Removed Views
26
Arrow Method for Removed Views
27
Views with Related Parts
28
Rotated Views

• Rotated from normal alignment with other views
• Avoid when possible, but may be necessary when
• Limited space
• Enlarge the view
• Keep all views on one sheet
• Angle and direction of rotation under the view
  title
• ROTATED 90CW
• ROTATED 90CCW

29
Projecting Chamfers

• Slanted edge or a line

30
Projecting Circles

• Line of sight perpendicular to a circular feature
• Feature appears round
• Circle projected onto an inclined surface
• View is elliptical in shape

31
Projecting Arcs
32
Projecting Rounded Corners

• Represented as a contour only
• Fillets
• Rounds
• Break corners

33
Projecting Rounded Curves and Cylindrical Shapes

• Phantom lines sometimes used to accent rounded
  feature

34
Runouts
35
Line Precedence

• Object lines take precedence over hidden lines
  and centerlines
• Hidden lines take precedence over centerlines
• Cutting-plane lines take precedence over
  centerlines

36
Line Precedence
37
Glossary

• Break corner
• A sharp corner with a slight relief.
• Chamfer
• The cutting away of the sharp external or
  internal corner of an edge.
• Descriptive geometry
• A drafting method used to study 3-D geometry with
  2-D drafting applications where planes of
  projections analyze and describe the true
  geometric characteristics.

38
Glossary

• Fillets
• Slightly rounded inside curves at corners,
  generally used to ease the machining of inside
  corners or to allow patterns to release more
  easily from castings and forgings.
• Multiview drawing
• Represents the shape of an object using two or
  more views.
• Multiview projection
• Establishes views of an object projected upon two
  or more planes of projection by using
  orthographic projection techniques.

39
Glossary

• Multiviews
• Two-dimensional views.
• Orthographic projection
• Any projection of the features of an object onto
  an imaginary plane called a plane of projection.
• Related part method
• Showing a part or parts that are next to the part
  being detailed.

40
Glossary

• Rounds
• Rounded outside corners that are used to relieve
  sharp exterior edges.
• Runouts
• The characteristics of intersecting features with
  circular objects are projected in multiview to
  the extent where one shape runs into the other.
• True geometry view
• The view that shows the actual shape of the
  object.