1. 1 Reminder-Instructions for equipment  Tutorial 4 onwards you will bring the following  Approximately 21.5 x 15 in. drawing sheets  Cello tape for fixing sheet to desk  Compass (small and big)  Divider  Pencils (H and 2H)  More H  lighter  Mini drafter  Metric scale and eraser

2. 2 Mini Drafter (Tutorial 4 onwards) A mini drafter is a portable device used to draw parallel, inclined and perpendicular lines speedily. It is mounted on a drawing board at the top left corner. A drafter consists of a scale, a scale screw, a scale plate, steel bars, a bar plate and a clamping mechanism

3. a, d f, gb, c e, h da bc he f g Oblique projection Plane of projection Projection lines are oblique to the plane d, h b, fc, g a, e Face abcd retains original shape and dimensions

4. Drawing an oblique projection   taken as 45 o Oblique view of a cuboid x y z Axes are drawn such that two of them are perpendicular to each other for the front face (horizontal and vertical) and the third is drawn at a pre-defined angle (use 45 o in this course) to horizontal axis Lines drawn in true length Receding angle Receding line This face will have features with true shape Draw essential contours (circles, curves etc.) on this face o

5. Oblique view  It is a method of drawing a 3-D view of an object (similar to isometric view)  2 axes are mutually perpendicular while the 3 rd. axis is at an angle (other than 90 o to the other 2 axes)

6. Object Orientation Guidelines Place complex features (arc, hole, irregular shape surface parallel to frontal plane.

7. Cavalier and cabinet projection Two types of oblique projection – Cavalier projection: When the receding lines are drawn to full size scale and the projectors are inclined at an angle of 30 o, 45 o, or 60 o – Cabinet projection: If the receding lines are drawn to half size scale. We use Cavalier Projection in this course

8. 8 PROJECTIONS OF PLANES Information usually given: 1.Shape of the plane 2.Inclination of it’s surface with one of the reference (principal) planes 3.Inclination of one of it’s edges with the other reference plane will be given  A plane is a two-dimensional geometrical entity  It has length and width but no thickness  For practical purposes, a flat face of an object may be treated as a plane  A plane which has limited extent (has fixed shape) is termed as a lamina

9. 9 HP a1a1 b1b1 c1c1 d1d1 VP a’ d’ c’c’ b’ VP a’ d’ c’b’ For Fv For Tv For F.V. For T.V. For F.V. HP a bc d a1’a1’ d1’d1’ c1’c1’ b1’b1’ a1a1 b1b1 c1c1 d1d1 SURFACE PARALLEL TO HP PICTORIAL PRESENTATION SURFACE INCLINED TO HP PICTORIAL PRESENTATION ONE SMALL SIDE INCLINED TO VP PICTORIAL PRESENTATION ORTHOGRAPHIC TV-True Shape FV- Line // to xy ORTHOGRAPHIC FV- Inclined to XY TV- Reduced Shape ORTHOGRAPHIC FV- Apparent Shape TV-Previous Shape ABC

10. 10 X Y a b c d a’ b’ c’d’ a1a1 b1b1 c1c1 d1d1 a1a1 b1b1 c1c1 d1d1 b’a’ d’c’ c’ 1 d’ 1 b’ 1 a’ 1 45 0 30 0 Rectangle 30mm and 50mm sides is resting on HP on one small side which is 30 0 inclined to VP, while the surface of the plane makes 45 0 inclination with HP. Draw it’s projections. Surface // to HpSurface inclined to Hp Side Inclined to Vp

11. 11 Drawing the side view O 45 o T F F T RSV With O as center draw curves (1/4 circle) to project the corners Draw a line from O at 45 o to the horizontal axis to project the corners w w w wO

12. 12 Projections of solids

13. 13 SOLIDS Dimensional parameters of different solids. Top Rectangular Face Longer Edge Base Edge of Base Corner of base Triangular Face Slant Edge Base Apex Square PrismSquare Pyramid Cylinder Cone Edge of Base Apex Base Generators Imaginary lines generating curved surface of cylinder & cone. Sections of solids( top & base not parallel) Frustum of cone & pyramids. ( top & base parallel to each other)

14. Problem: A cone 40 mm diameter and 50 mm height is resting on one generator on Hp which makes 30 0 inclination with Vp Draw it’s projections. Draw in 1 st.angle h a b c d e g f X Y a’b’ d’ e’c’g’g’ f’h’ o’ a’ h’b’ e’ c’g’ d’f’ o’ a1a1 h1h1 g1g1 f1f1 e1e1 d1d1 c1c1 b1b1 a1a1 c1c1 b1b1 d1d1 e1e1 f1f1 g1g1 h1h1 o1o1 a’ 1 b’ 1 c’ 1 d’ 1 e’ 1 f’ 1 g’ 1 h’ 1 o1o1 o1o1 30 Solution Steps: Resting on Hp on one generator, means lying on Hp: 1.Assume it standing on Hp. 2.It’s Tv will show True Shape of base( circle ) 3.Draw 40mm dia. Circle as Tv & taking 50 mm axis project Fv. ( a triangle) 4.Name all points as shown in illustration. 5.Draw 2 nd Fv in lying position I.e.o’e’ on xy. And project it’s Tv below xy. 6.Make visible lines dark and hidden dotted, as per the procedure. 7.Then construct remaining inclination with Vp ( generator o 1 e 1 30 0 to xy as shown) & project final Fv.