5 isometric views

Engg Drawing Isometric View

1. ENGINEERING DRAWING Lecture 5
Isometric Views:
Isometric views are a simple way of representing a three dimensional object so that the
complexities of a shape can be clearly understood.

It is a type of graphical projection in which all three dimensions of an object are shown in one
view Orthographic view shows only two dimensions in any particular view. This makes it
difficult to interpret them and only technically trained person can interpret the meaning of
these orthographic views. A nontechnical person cannot imagine the shape of the object from
orthographic projections. Whereas, pictorial projections can be easily understood even by
persons without any technical training because such views show all the three dimensions of an
object in the same view. But pictorial view does not show the true shape and size of any
principal surface of an object and it does not show the hidden portions. Pictorial projections are
easy to imagine so these are normally used.
An isometric view of an object can be obtained by
choosing the viewing direction such that the angles
between the projections of the x, y, and z axes are all the
same, or 120°. An isometric uses a plan grid at 30 degrees
from the horizontal in both directions .An isometric graph
can be used to make this kind of drawing.

2.  Isometric Axes: The lines AB, AD and AE meeting at a point A and making an angle of
120 degrees with each other are termed “isometric axes”
 Isometric Lines: The lines parallel to the isometric axes are termed isometric lines. The
lines CD, CB etc are examples of isometric lines.
 Non-isometric Lines: The lines which are not parallel to isometric axes are termed non-
isometric lines. The BD is an example.
 Isometric Planes: The planes representing the faces of the rectangular prism as well as
other planes parallel to these planes are termed isometric planes.

3. Isometric Scale
Edges of objects appear shorten (foreshorten) when a view is taken which is not perpendicular
to them. An isometric scale is often used to represent this shortening effect on drawing so that
the resulting isometric views look more real. An Isometric drawings can be drawn using
ordinary scale or isometric scale.
1. To draw an isometric scale, First, Line
AB and AB1 are drawn at 30
o
and 45
o

angles respectively.
2. True length is marked on line AB1.
3. Vertical projections are drawn from
marked points on line AB1 to AB. The
intersecting points on AB represent the
isometric length corresponding to true
length projected.
Steps to Make An Isometric View.
1. Isometric sketches begin with defining isometric axes, three lines, one vertical and two
drawn at 30° from the horizontal.

2. Three lines of the isometric axes(x,y,z) represent the three primary dimensions of the
object: width, height, and depth

4. 3. Draw the font face of the isometric block along the defined axes.

4. Draw the rest of the isometric block. In this case left view of the block is drawn.

5. Add details to the block starting from the front face. Then add details to the other faces.

6. Darken all visible lines to complete the isometric sketch. (Make sure that construction
lines are light)

5. Figure 1


Figure 2

6. Figure 3

Figure 4

7. Example Problem: Draw a scaled isometric view from given orthographic views (Plan and
Elevation). Use Isometric Scale.