# Design, Drawing & Importance of Safety: Development of surfaces & Isometric drawing

By Akhil Gupta|Updated : May 24th, 2021

ISOMETRIC PROJECTION

1. Introduction

In an isometric projection, the plane is placed in such a way that all the, three visible sides of the object make the same angle with one another. In this way, all the three sides meet at a point making an angle of 120° with one another. These lines are called Isometric Axes.

In the figure, the lines which are parallel to these lines are called isometric lines, and those lines which are not parallel to these lines are called Non-isometric Lines.

Two isometric axes make an angle of 30° with the horizontal line. While the third axis makes an angle of 90°. 1. Isometric Scale:

Since, in isometric projection, the isometric line makes an angle of 30° with the horizontal lines, therefore, their length is not equal to the actual length, but it is only 81.5% of the actual length.

### 2.     Difference between  Isometric Drawing and Isometric Projection.

The method of drawing of Isometric Drawing and Isometric Projection is the same.

All the dimensions in the isometric drawing are actually while in the Isometric projection, the isometric scale is to be used. As a result, the dimensions are less than the actual ones.

#### 3.      Isometric lines, circles, and curves;

The lines which are drawn parallel to the isometric axes in forming isometric projection are called isometric lines. The represented length is not equal to the actual length, but it is 82% of it.

Isometric circles are also not the actual circles, but they are elliptic ones: For drawing such circles, first of all, the isometric square is constructed. Then the four centers of an ellipse are shown. These are in fact, the points of intersection of the corner of the bigger angle of the isometric square and the bisector of the sides confronting it.

The circle is completed by drawing arcs from these points. If some other arc is to be constructed, then the same method is to be adopted.

## 4.      Methods OF Drawing Isometric Drawing.

Following are the two methods of drawing isometric drawing:

1. Box Method.
2. Off-set Method. ### A . Box Method:

This method of drawing isometric drawing is easy and intelligible. However, it takes much time for the drawing. In this method, the maximum length, breadth, and height of an object are noted.

A box is constructed in accordance with these dimensions. These dimensions of the box are represented according to isometric projection. These make angles of degrees 30, 30 and 90 with the horizontal line.

### B . Off-set Method:

In this method, for preparing an isometric view, by selecting the side, the length, and breadth of the object are drawn parallel to the isometric axis. After this, the other isometric and non-isometric lines are drawn according to the dimensions.

Lastly, circles and curves are drawn, and the drawing is completed by erasing extra lines.

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