Lesson Notes By Weeks and Term - Junior Secondary 3

Drawing practices - Oblique drawing

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TERM – 3RD TERM

WEEK EIGHT

Class: Junior Secondary School 3

Age: 14 years

Duration: 40 minutes of 5 periods each

Date:

Subject: BASIC TECHNOLOGY

Topic:  DRAWING PRACTCES –OBLIQUE DRAWING

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

  1. Define oblique drawing
  2. Identify types of oblique drawing
  3. Construct Simple Objects using oblique projection

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures, mathematical sets, drawing instruments

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S

ACTIVITY

STEP 1

INTRODUCTION

The teacher explains the meaning of oblique projection.

Students pay

attention

STEP 2

EXPLANATION

Teacher discusses the types of oblique projection.

Students pay

attention and

participate

 

STEP 3

DEMONSTRATION

Teacher guide students to construct simple objects in oblique views

Students pay

attention and

participate

STEP 4

NOTE TAKING

The teacher writes a summarized

note on the board

The students

copy the note in

their books

 

NOTE

 DRAWING PRACTCES –OBLIQUE DRAWING

Oblique projection is a simple type of technical drawing of graphical projection used for producing two-dimensional (2D) images of three-dimensional (3D) objects.

Types of Oblique Projection

Following are the types of oblique projections according to construction.

  1. Cavalier Oblique Sketching

This kind of drawing is typically created using oblique projection. In this diagram, the third axis is at a 45° angle to the horizontal line, with the first two axes being vertical and the third being horizontal.

  1. Cabinet Oblique Sketching

In this diagram, the third axis is at an angle of between 30 and 60 degrees to the horizontal line, with the two other axes being vertical. Such a drawing closely mimics the original picture. The scale on the inclined plane is 1/2 or 2/3 of the actual size, whilst the dimensions on the horizontal and vertical axes are given from the true scale.

  1. Normal Oblique Sketching

Normal oblique drawings use depth lines that are only three-fourths the length of the depth established by the three-view drawing

Procedure for oblique projection

Creating an oblique drawing involves these steps:

  1. Choose Scale: Decide on the scale for your drawing.
  2. Draw the Horizontal Line: Sketch the horizontal line, representing the ground or base of the object.
  3. Draw the Vertical Lines: Using a 45⁰ set square and a tee square, d raw vertical lines from the endpoints of the horizontal line, indicating the height of the object.
  4. Draw Receding Lines: Extend lines from the top and bottom corners of the vertical lines at a chosen angle (usually 45 degrees), creating the depth of the object.
  5. Complete the Shape: Connect the endpoints of the receding lines to form the shape of the object.
  6. Add Details: Add any necessary details or features to the drawing.


EVALUATION: 1. What is oblique projection?

  1. Mention and describe the types of oblique projection
  2. Identify the procedure for oblique projection.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively