ISOMETRIC PROJECTIONS

CLASS NOTES FOR

MECHANICAL ENGINEERING

 

Isometric projections is a single view projection

of a three dimensional solid. Draw three axis

at 120⁰. Use isometric scale for these projections.

It is 3-dimensional 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 120⁰ 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 30⁰ and 45⁰ to the horizontal from a certain point. Laid true dimensions on 45⁰  angle line. Draw vertical lines from these markings on 30⁰ line. Now the dimensions obtained on the 30⁰ 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

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

2.  Draw  the isometric projections using plane figures. Plane figures make up a solid.

Methods Of Drawing Isometric Of Plane Figures

1. Methods of points

2.  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 

1. Cubical objects

2. Box type objects

3. Prismatic objects

4.  Pyramid type objects

5.  Cylindrical objects

6.  Conical objects

7.  Spherical objects

 

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