SUBJECT : BASIC TECHNOLOGY
CLASS : JSS 3
TOPIC : DRAWING PRACTICES (PICTORIAL DRAWING)
THE OBLIQUE DRAWING
The oblique drawing is a pictorial method of drawing the shape of solid object in which the receding lines are drawn at an angle 45° to the horizontal plane. It recognizes solid objects in three dimensions (Length, width and depth).
How to draw oblique axes
The practical steps in drawing oblique axes involve:
The oblique method is based on three axes, but two of these are at right angles to each together (perpendicular) and the third axis is at angle 45°. The first axis is vertical OB, the second axis is horizontal OD. An object drawn on these first-two axis has one face parallel to the vertical plane and is therefore called a true elevation. Set-squares are usually used for convenience.
There are two (2) types of oblique drawings, these are:
Cabinet drawing: This is the oblique drawing in which the slanting sides are drawn half (1/2) the full size. If the cube measures 30mm, the length of the slanting side will be 15mm. This is preferred to cavalier type.
Cavalier drawing: This is the oblique drawing in which the slanting sides are drawn full size.
Note: The slanting sides of an oblique drawing are usually drawing at an angle 45 degree to the horizontal plane.
Procedures/Steps:
Step I: Set your paper on the drawing board, using cello tape.
Step II: Draw the boarder line (10mm=1cm) from the margin.
Step III: Draw the title block, supported by the use of T-squares.
Step IV: Remove the set square and draw the base of the vertical line (a short continuous line).
Step V: Consider the block object of a given length (L), Breadth (B) and Height (H).
Step VI: Measure the length (L) along OA on the receding axes. Measure the breadth (B) along OC on the receding axes.
Step VII: Then draw the oblique box.
Step VIII: Draw the correct shape of the object with thick continuous line (i.e outline.)
ASSIGNMENT:
1) Define Pictorial drawing.
2) Explain Oblique drawing.
3) List the two ways of Oblique drawings.