Auxiliary and true shape

Lecture 4 Friday, 18 August 2017 1
ENGINEERING GRAPHICS
Auxiliary Views

Auxiliary View
An auxiliary view is an orthographic view taken in
such a manner that the lines of sight are not parallel
to the principal projection planes (frontal, horizontal,
or profile). There are an infinite number of possible
auxiliary views of any given object.
Principal faces of the object are not parallel to PP
planes.

Why Auxiliary View?
• Inclined planes and oblique
lines do not appear true
length or true size in any of
the principle planes of
projection
• To determine the true
length of an oblique line or
the true size of an inclined
plane, an auxiliary view
must be created.
• The auxiliary view shows
the true shape and size of
circular shapes.

Steps of Drawing
1. Select the face that is to be drawn as
i) a true surface,
ii) a true length line,
iii) an end view of a line.

Steps of Drawing
2. Draw construction lines perpendicular to the
surface/line/point of interest. This line
should go in a direction, and far enough
that leaves enough space for the view.

Steps of Drawing
3. Draw a folding line at an appropriate
distance. This will act as a reference
plane.

Steps of Drawing
4. Transfer distances from another view
(adjacent view). This view will typically be
the view adjoining the view that the auxiliary
is drawn from.

Steps of Drawing
5. Complete the view. Draw visible and hidden
lines as seen from the direction of
projection lines.

Example 2
1. Draw two orthographic views and assume
a direction of sight for auxiliary view.

Steps of Drawing
2. Draw construction lines parallel to the
arrow.

Steps of Drawing
3. Assume reference plane coinciding with
back surface. Draw reference plane (edge
view) in the top view and auxiliary view.

Steps of Drawing
4. Draw auxiliary view of surface A. Transfer
depth measurements from top view.

Steps of Drawing
5. Complete the view by adding other visible
edges and objects.

Curved Object

Classification of Auxiliary Views
• Auxiliary views are classified according
to the principal dimension of the object
shown in the view.
1. Depth/Front auxiliary view
2. Height/Top auxiliary view
3. Width/Side auxiliary view

Depth Auxiliary View
Any auxiliary view projected from the ‘elevation’ showing depth
of object
Elevation is the adjacent view, Plan and Side-View are
alternative views
Direction of sight

Height Auxiliary View
Any auxiliary view projected from the plan showing height of
object
Plan is adjacent view, Side-View and Elevation are
alternative views
Direction of sight

Width Auxiliary View
Any auxiliary view projected from the side-view showing width of
object
Side-View is adjacent view, Plan and Elevation are alternative
views
Direction of sight

Notes
• An auxiliary view is an orthographic view taken on
planes other than principal projection (PP) planes
(frontal, horizontal, or profile).
• Principal dimension shown in auxiliary view is not
shown in the adjacent view from which auxiliary
view is projected.
• A primary auxiliary view is projected on the plane
perpendicular to one PP plane and inclined to
other 2 PP planes.
• A secondary auxiliary view is projected from
primary auxiliary views.

Other Auxiliary Views
• Any auxiliary view projected from the
primary auxiliary view is secondary
auxiliary view

Example

Auxiliary and true shape

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Recently uploaded

Recently uploaded (20)

Auxiliary and true shape