DFTG-1333 – Mechanical DraftingPrepared by Trung Bui, Instructor

_____________________________________________________

Session 12

Auxiliary Views

Geisecke’s textbook:

15th Ed. Chapter 9 – From p.362

Update: 17-1201

What is an Auxiliary View?

Many objects are shaped so that their

principal faces are not parallel to the

standard planes of projection.

To show the true circular shapes, we use a

direction of sight that is perpendicular to

the plane of the curve. It is Auxiliary View.

Auxiliary views are useful for both design

and documentation.

Auxiliary View

Rules

-Parallel

-Perpendicular

-True Size

Understanding Auxiliary Views

Understanding Auxiliary Views

The Auxiliary Plane

To show the inclined surface (P) true size, the

direction of sight must be perpendicular to the

inclined plane.

The auxiliary plane in this case is perpendicular

to the frontal plane of projection and

hinged to it. It is angled to the horizontal (top)

and profile (side) viewing planes.

Primary Auxiliary Views

A primary auxiliary view is projected onto a plane that is perpendicular to one

of the principal planes of projection and is inclined to the other two.

OBJECTIVES

1. Create an auxiliary view from orthographic views.

2. Dimensioning auxiliary views.

3. Auxiliary plane.

PROCEDURES

1. Create an auxiliary view from orthographic views.

2. Draw folding lines or reference-plane lines between any two adjacent views.

3. Construct depth, height, or width auxiliary views.

4. Plot curves in auxiliary views.

5. Construct partial auxiliary views.

6. Create auxiliary section views.

7. Produce views to show the true length of a line, point view of a line, edge view

of a surface, and true-size view of a surface.

8. Show the true size of the angle between two planes (dihedral angle).

9. Construct the development of prisms, pyramids, cylinders, and cones, if any.

10. Use triangulation to transfer surface shapes to a development.

11. Create the development of transition pieces.

12. Graphically solve for the intersection of solids.

13. Apply revolution to show true-length edges and true-size surfaces.

Orthographic Projection

Three principal planes of projection hinged together

Orthographic Projection

Three principal views of projection hinged together

Orthographic Projection (cont.)

Views removed showing three regular (top, front, side) views

Auxiliary Views

Tow principal views plus an auxiliary plane hinged together

Auxiliary Views

Auxiliary Views

Auxiliary Views

Tow principal planes plus an auxiliary plane hinged together

Auxiliary View

Planes removed showing front, side, and auxiliary views

Auxiliary View Replaces Right Side View

Only a partial top view is required. It shows the true shape of the recess.

Only a partial auxiliary view is required. It show the true shape of the

Surface A

Auxiliary View Replaces Top View

Only a partial Top view is required. It shows the true shape of the recess.

Only a partial Auxiliary view is required. It show the true shape of the

Surface A

Dimensioning Auxiliary View

Exercise 1

Projectting an Auxiliary View

Exercise 1

The object has been numbered in the pictorial view to aid in keeping track of

the vertices. To create an auxiliary view of surface A, follow these steps:

Exercise 1

1. Draw two views of the object:

Front view and Top view

Exercise 1

2. Determine the direction of

sight and the depth of top

view.

Exercise 1

3. Draw line R-P of

reference plane that

parallels with line

surface A.

Exercise 1

4. Projecting points 1, 2

and 7:

The reference lines on

the Top and Auxiliary

views are at right angles

to the projection lines.

These are the edge

views of the reference

plane.

Exercise 1

5. Projecting points 5 and 8:

Each point in the auxiliary

view will be on its

projection line extended

from the Front view. The

point will be the same

distance from the reference

line on the Top view to the

corresponding reference

line in the Auxiliary view.

Exercise 1

6. Connecting the

vertices (peak) in

the same order as

them shown

connecting in the

Top view

points 7 and 8.

Exercise 1

7. Connecting the

vertices in the

same order as

shown connecting

in the Top view

points 1 and 7.

Exercise 1

8. Connecting the

vertices in the same

order as them

shown connecting

in the Top view

points 1 and 2.

Exercise 1

9. Connecting the

vertices in the

same order as them

shown connecting

in the Top view

points 2 and 5.

Exercise 1

10. Connecting the

vertices in the same

order as them shown

connecting in the Top

view points 5 and 8.

Exercise 1

11. Projecting points 4, 3, 6

and 9: (same projecting

point 5, 8)

Note that two surfaces of the

object appeared as lines at

the Auxiliary view.

Connecting in the Front view

points 8 and 9

Exercise 1

12. Connecting in the Front view

points 5 and 6.

points 2 and 3.

Exercise 1

13. Connecting in the top view

points 3 and 6.

points 6 and 9.

Exercise 1

13. Auxiliary

view shown

Exercise 1

13. Auxiliary

view shown

Circles And Ellipses

In Auxiliary Views

Circular shapes appear elliptical when viewed at an angle other than 90° (straight

on to the circular shape). This is frequently the case when constructing auxiliary

views.

Exercise 2

Projectting an Inclined Circles and

Ellipses in Auxiliary View

Exercise 2

Given the front and right side views shown, use these steps to project an

auxiliary view showing the true size of the elliptical surface.

Exercise 2

Should use a reference plane through the center of the object, as shown:

Exercise 2

Should draw the reference line parallel with surface

Exercise 2

Should select points on the circle in the side view:

Exercise 2

Project each point to the front view

Exercise 2Project each point to the auxiliary view along its projection line. In the case,

the direction of sight is perpendicular to the edge view of the inclined

surface.

cTransfer distance from the side view to the auxiliary view. Two points can be

located with each measurement, as shown for points 1-2,3-4, and 5-6.

Auxiliary View

Using Grid Paper To Sketch

Auxiliary Views

You can use grid paper

to help sketch auxiliary

views by orienting

the lines of the grid

paper underneath your

vellum or other

semitransparent

drawing sheet so that

the grid is parallel to

the inclined edge in the

drawing…

Hidden Lines

In Auxiliary Views

Your instructor may ask you to show all hidden lines

for visualization practice, especially if the auxiliary

view of the entire object is shown. Later, when you are

familiar with drawing auxiliary views, omit hidden

lines when they do not add needed information to the

drawing.

Generally,

hidden lines

should be

omitted in

auxiliary views,

unless they are

needed to

clearly

communicate

the drawing’s

intent.

Auxiliary Sections

An auxiliary section is simply an auxiliary view in section.

Note the

cutting-plane line and the terminating arrows that indicate the direction

of sight for the auxiliary section. In an auxiliary section

drawing, the entire portion of the object behind the cutting plane

may be shown, or the cut surface alone may be shown.

The End