TA 101: Technical Arts 2015-16 II Dr. Prishati Raychowdhury Department of Civil Engineering IIT Kanpur Office: FB 336; Phone: 6692 E-mail: prishati@iitk.ac.in

Isometric Projection & Oblique Projection Lecture 8 Isometric Projection & Oblique Projection

Notice Make-up Lab on Friday, 29th January, 2016 [For Tuesday Batches: B1, B2, B3] Time and venue remains the same: [Northern Drawing Hall, 10 am- 1 pm]

Isometric view: Example 1 D1 D1 L2 L2 H2 L2 D1 H1 H3 L1 H2 H1 L2 L1 H3 D1

Use of GRID Sheets with 30o lines

Example 2: Using Isometric Grids H D Non-isometric Plane Isometric Plane H L D Normal Grid Isometric Grid

Isometric View: Example 3

Isometric View: Example 4 8

Offset/Coordinate Method When an object is made up of planes at different angles (i.e. most of the edges are non-isometric lines), it is better to locate the ends of the edges by offset method, rather than boxing Perpendiculars are extended from each end point of the edge to an isometric reference plane These perpendiculars, which are isometric lines, are located on the drawing by isometric coordinates

Example 1: Pentagonal Pyramid EF OF O’F DF CF BF AF O P S R Q A B C D E P S R Q A B C D E O O’ Isometric View of Pentagonal Pyramid

Example 2: Truncated Triangular Pyramid O O p p A A C q O B C B q

Next Topic Oblique Projections

Oblique Projection OBLIQUE ORTHOGRAPHIC ISOMETRIC Front Face in TRUE SHAPE OBLIQUE ORTHOGRAPHIC ISOMETRIC

Plane of projection PARALLEL PROJECTORS OBLIQUE (NOT PERPENDICULAR) TO THE PLANE Plane of projection

Oblique Projections Details along depth axis True Shape 300 to 600 Isometric Oblique The oblique method is mainly used for objects with circular or curved features only one face or on parallel faces For objects of this type the oblique is easy to draw and dimension This is an widely used pictorial view

Oblique Projections An oblique view is formed by parallel projectors that make an angle other than 900 with the projection plane The object is not rotated or tilted and has a major face parallel to projection plane so that the front face of the object is seen in its true shape The height and width of the object remain at 900 to each other (front face) The details of the object along the depth are shown along a depth axis taken at an arbitrary angle (normally 300 or 450) The depth direction may be taken either left or right, and up or down

Steps Draw a rectangle –overall width and height of the object Extend parallel lines from each corner of the box back at an angle (30o or 45o) Mark the extension lines at a point equal to the depth of the object Connect the depth of lines to form a box Add any details such as holes, notches, onto the front view (True size & True Shape) Extend the details the depth of the object Complete sketch by darkening in the object

Oblique Drawing Example 1 300

Oblique Drawing Example 1

Thank you..