1. Lecture 5 Tuesday, 16 June 2015 1 ENGINEERING GRAPHICS 1E7 Lecture 5: Isometric Projections

2. Lecture 5 Tuesday, 16 June 2015 2 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

3. Lecture 5 Tuesday, 16 June 2015 3 Notes Objects composed entirely of isometric lines can be drawn by taking all measurements parallel to main edges of the enclosing box. In an isometric drawing, an angle never appears in its true size. Non-isometric lines are drawn by transferring the ordinates (which are on isometric lines) of the end of the lines

4. Lecture 5 Tuesday, 16 June 2015 4 Objects with Normal Surfaces Make an Isometric Drawing with corner A at the bottom

5. Lecture 5 Tuesday, 16 June 2015 5 Objects with Normal Surfaces

6. Lecture 5 Tuesday, 16 June 2015 6 Objects with Oblique Surfaces Make an Isometric Drawing with corner A at the bottom NON-ISOMETRIC LINE

7. Lecture 5 Tuesday, 16 June 2015 7 Objects with Oblique Surfaces

8. Lecture 5 Tuesday, 16 June 2015 8 Objects with Non-isometric Lines Make an Isometric Drawing with apex A facing front

9. Lecture 5 Tuesday, 16 June 2015 9 Objects with Non-isometric Lines Non-isometric lines are drawn with box construction and offset measurements Non-isometric lines are not drawn in true length in isometric drawing (BA is shorter than CA in this drawing)

10. Lecture 5 Tuesday, 16 June 2015 10 Irregular Objects Make an Isometric Drawing of the following irregular object (pyramid)

11. Lecture 5 Tuesday, 16 June 2015 11 Irregular Objects OA and OB offsets help to locate apex O Complete box construction may not be needed in each case

12. Lecture 5 Tuesday, 16 June 2015 12 Notes Axonometric projection shows all 3 dimensions, length, width and height The isometric lines are only drawn to scale. Inclined and oblique surfaces are drawn using end coordinates Angles, irregular curves require special techniques Box construction and offset measurements are common methods