ISOMETRIC PROJECTIONS CLASS NOTES FOR MECHANICAL ENGINEERING
ISOMETRIC PROJECTIONS
CLASS NOTES FOR
MECHANICAL ENGINEERING
Isometric projections is a single view projection
of a three dimensional solid. Draw three axis
at 120^{0}. Use isometric scale for these projections.
It is 3dimensional view of an object on a reduced
scale. Sizes on this are 81.5 % of the true sizes.
Draw the isometric view from given front view,
top view and side view. Front, top and side views in
orthographic projections contain only true dimensions.
Isometric Axes
Three lines drawn 120^{0 }to each other are isometric axes.
Isometric Lines
Lines parallel to isometric axes are isometric lines.
Isometric Planes
Planes formed with isometric axes and isometric lines are isometric planes.
Lines OA, OB & OC are isometric axes
Lines CD parallel to OB, BF parallel to OA, DB parallel to OC are isometric lines
Planes OAFBO, OBDCO are isometric planes
Isometric Scale
Fig. Isometric Scale
This scale gives the apparent dimensions for the isometric projections. Draw two lines at 30^{0} and 45^{0 }to the horizontal from a certain point. Laid true dimensions on 45^{0 }angle line. Draw vertical lines from these markings on 30^{0} line. Now the dimensions obtained on the 30^{0} line gives the isometric dimension. These dimensions are 81.9 % of the true dimensions.
Isometric Drawing Or Isometric View
Draw isometric projection with true dimensions. it is an isometric drawing or isometric view. Dimensions of isometric views are real dimensions.
Isometric Projection
Draw the 3 dimensional isometric projection with isometric dimensions. It is an isometric projection. An Isometric projection is smaller than the actual object.
Steps To Draw The Isometric Projections/Isometric View/Isometric Drawing

First draw the isometric projections of plane figures like a rectangle, square, triangle, circle, pentagon, hexagon etc.

Draw the isometric projections using plane figures. Plane figures make up a solid.
Methods Of Drawing Isometric Of Plane Figures

Methods of points

Four centers method
What will be the shape is in isometric projections for a?
(i) Square
It is a rhombus.
(ii) Circle
It is an ellipse.
(iii) Rectangle
It is a parallelogram.
9iv) Sphere
It is a circle.
Draw isometric projections for

Cubical objects
 Box type objects

Prismatic objects

Pyramid type objects

Cylindrical objects

Conical objects

Spherical objects
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