ENGINEERING GRAPHICS 1E9 Lecture 4: 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 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 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. Depth/Front auxiliary view Height/Top auxiliary view 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

Example