Free hand sketching

BASIC SCIENCE JSS1 third term

Sub-Theme: Safety, Material and Processing

Theme Understanding Basic Science and Technology

WEEK 1

Freehand sketching

Performance objectives

Students should be able to:

1. Define freehand sketching
2. Make neat freehand sketches of lines, curves, and irregular shapes

Content

Freehand sketching

This is a quick and convenient way of describing the shape of an object. Freehand sketching is the quickest method to describe the shape of an object. It can be communicated to others without the use of any drawing instruments except a pen or pencil.

It is a drawing made without the use of drawing instruments, for instance, a simple sketch of a building or structure will give an insight to what the designer intends to build for his or her client. The ability to make freehand sketches is a valuable asset acquired through regular practice which helps to develop one’s ability to observe details in an object and later describe it on paper.

Materials required for freehand sketching

The following are freehand sketching materials

1. Drawing sheet or paper
2. Soft eraser
3. Drawing pencils
4. Razorblade or sharpener

                                                                                                                             

                                                                            Freehand sketching

Sketching techniques

Sketching a straight line

A straight line is a short distance between two points.

A straight line can be sketched using a dash or dot far enough to the right-hand side of the drawing sheet. Start to draw a line from the left hand to join the dash or dot with your eyes fixed on the point.

                                                                                

Sketching curve

This is done by plotting some points not too far from each other at different level later join all the plots point together as shown below.

Sketching a circle

To draw a circle, the easiest way is to draw lines which are equal in diameter to the circle in different directions. Each line must be drawn as faint and straight as possible, each crossing one another at a central point.

Then join the point by little curve from the tip of each line. Try to draw another circle by means of joining two large curves having half the size as radius and full size in diameter.

Sketching a square box

This can be sketched in an isomeric or oblique view. An isomeric view has an inclined vertical height and baseline at 30⁰ to the horizontal. An oblique view has the height vertical and one baseline inclined at 45⁰ to the horizontal while the second baseline is horizontal. Once it s decided which view to represent, the block is drawn by using a series of straight lines both vertical and horizontal, applying the techniques discussed earlier.

                          

                                     Isomeric square block

Sketching an irregular edge

Figures with an irregular edge are first drawn by sketching a rectangular or square block which can completely contain the object. The shape is then carefully shaped by using dotted lines to show the desired shape with appropriate curves.