1. Lecture 5 Monday, 29 June 2015 1 ENGINEERING GRAPHICS 1E7 Lecture 5: Isometric Projections

2. Lecture 5 Monday, 29 June 2015 2 What is ISOMETRIC? It is a method of producing pictorial view of an object showing all three faces of the object simultaneously. It is a type of parallel projection It is a type of axonometric projection

3. Lecture 5 Monday, 29 June 2015 3 Axonometric Projections Observer at infinity Projectors parallel to each other and perpendicular to projection plane Object is inclined with respect to projection plane

4. Lecture 5 Monday, 29 June 2015 4 Types of Axonometric Projections Isometric Projection Dimetric Projection Trimetric Projection

5. Lecture 5 Monday, 29 June 2015 5 Isometric Projections All angles between axonometric axes are equal The three coordinate axes of the object appear equally foreshortened (about 3/4 th of true length) The angles between any two of the three coordinate axes is 120°

6. Lecture 5 Monday, 29 June 2015 6 Isometric Terminology The three coordinate axes are called isometric axes Any line parallel to isometric axes is called isometric line A non-isometric line is a line not parallel to any one of the three isometric axis In isometric projection of cube, the faces of the cube and any plane parallel to them is called isometric planes

7. Lecture 5 Monday, 29 June 2015 7 Isometric Scale True lengths of the edges of the object are equally foreshortened Correct isometric projection can be drawn using an isometric scale (always smaller than ordinary scale)

8. Lecture 5 Monday, 29 June 2015 8 Isometric Drawing Isometric Projection: Drawing prepared with isometric scale on isometric axes Isometric Drawing: Drawing prepared with ordinary scale on isometric axes

9. Lecture 5 Monday, 29 June 2015 9 Steps: Step 1 Isometric sketches begin with defining isometric axes, three lines, one vertical and two drawn at 30° from the horizontal.

10. Lecture 5 Monday, 29 June 2015 10 Steps: Step 2 Three lines of the isometric axes represent the three primary dimensions of the object: width, height, and depth

11. Lecture 5 Monday, 29 June 2015 11 Steps: Step 3 Draw the font face of the isometric block.

12. Lecture 5 Monday, 29 June 2015 12 Steps: Step 4 Draw the rest of the isometric block.

13. Lecture 5 Monday, 29 June 2015 13 Steps: Step 5 Add details to the block starting from the front face. Then add details to the other faces.

14. Lecture 5 Monday, 29 June 2015 14 Steps: Step 6 Darken all visible lines to complete the isometric sketch. (make sure that construction lines are light)