By the end of this chapter, you will be able to:
These skills will help you create clear, precise pictorial drawings that are essential for communicating ideas and specifications in the technical trade.
A pictorial drawing is a single view of an object that shows its length, width and height together, so that the object looks much as it would to the eye in real life. Unlike an orthographic drawing, which splits an object into separate flat views (front, side and plan), a pictorial drawing gives an immediate three-dimensional impression. In biomedical engineering, pictorial drawings are used to explain the shape of a component, a bracket, an enclosure or an assembly to people who may not read orthographic views easily, such as nurses, procurement officers and clients. Example: the biomedical workshop at Tenwek Mission Hospital in Bomet sends an isometric sketch of a damaged infusion stand clamp to a local fabricator so that a replacement can be made.
| Type | Main feature | Typical use |
|---|---|---|
| Isometric | Three axes 120 degrees apart, two receding at 30 degrees to the horizontal, full size along all axes | Machine parts, enclosures, piping layouts |
| Oblique | Front face drawn true shape, depth drawn at an angle (usually 45 degrees) | Parts with circular or detailed front faces |
| Perspective | Lines converge to one, two or three vanishing points | Architectural views, product presentation |
| Dimetric and trimetric | Axes at unequal angles with different scales | Specialist technical illustration |
Isometric and oblique drawings are the methods used for engineering components at this level and are treated in detail in topic 1.2. Perspective drawing is mainly used for presentation, because lengths cannot be measured directly from it.
Technical drawings in Kenya follow international (ISO) standards adopted by the Kenya Bureau of Standards. ISO 5456-3 sets out axonometric representations, including isometric and dimetric drawing, and ISO 5456-2 covers orthographic representations. ISO 128 sets the types and thicknesses of lines used on all technical drawings. Following these standards means a drawing made in one workshop is read the same way by any engineer or fabricator.
Create a free account to open more of this chapter.
Free: practical guides, quick cards, workplace scenarios and more.
Create a free accountType: Individual
| Tools & Equipment | Materials |
|---|---|
| Drawing board | Drawing paper A3 size |
| T-square | Masking tape |
| Set squares (45° and 30°-60°) | |
| Isometric scale | |
| Drawing pencils (2H, HB, 2B) | |
| Eraser | |
| Sharpener | |
| Scale ruler (metric) |
| S/N | Item | Quantity |
|---|---|---|
| 1 | Drawing board | 1 Pc per Candidate |
| 2 | T-square | 1 Pc per Candidate |
| 3 | Set squares (45° and 30°-60°) | 1 set per Candidate |
| 4 | Isometric scale | 1 Pc per Candidate |
| 5 | Drawing pencils (2H, HB, 2B) | 3 Pcs per Candidate |
| 6 | Eraser | 1 Pc per Candidate |
| 7 | Sharpener | 1 Pc per Candidate |
| 8 | Drawing paper A3 size | 2 Sheets per Candidate |
| 9 | Masking tape | 1 roll per 10 Candidates |
| 10 | Scale ruler (metric) | 1 Pc per Candidate |
| Items to be Evaluated | Marks Available | Marks Obtained | Comments |
|---|---|---|---|
| TASK 1: PREPARATION AND SETTING UP | |||
| Wore appropriate PPE: gloves, dust coat, safety boots (Award 1 mark for all 3 PPE worn correctly or zero) | 1 | ||
| Cleaned and prepared the drawing board and work area (Award 1 mark for clean and organized work area) | 1 | ||
| Assembled the correct drawing tools and materials before starting (Award 1 mark for correct tools assembled) | 1 | ||
| Sub-Total | 3 | ||
| TASK 2: DRAWING EXECUTION | |||
| Used isometric scale and set squares correctly to construct isometric axes (Award 3 marks for accurate isometric axes construction) | 3 | ||
| Drew the mechanical component to correct size: 100mm length x 60mm width x 40mm height (Award 5 marks for dimensionally accurate drawing) | 5 | ||
| Applied correct line types and thicknesses (visible edges, hidden lines, construction lines) (Award 3 marks for appropriate line usage) | 3 | ||
| Maintained neatness and clarity throughout the drawing process (Award 2 marks for neat and legible drawing) | 2 | ||
| Sub-Total | 13 | ||
| PRODUCT CHECKLIST | |||
| Finished isometric drawing matches specified dimensions (100mm x 60mm x 40mm) with correct proportions and scale (Award 5 marks for dimensional accuracy and proportionality) | 5 | ||
| Drawing includes all required views and details as per instruction (Award 3 marks for completeness and correct detailing) | 3 | ||
| Drawing lines are crisp, clean and correctly weighted (Award 2 marks for line quality) | 2 | ||
| Sub-Total | 10 | ||
| GRAND TOTAL | 26 | ||
Type: Individual
| Tools & Equipment | Materials |
|---|---|
| Drawing board | Drawing paper A3 size |
| T-square | Set of reference dimensions and working drawing of the component |
| Set squares (45° and 30°-60°) | |
| Protractor | |
| Compass | |
| Pencils (2H, HB, 2B) | |
| Eraser | |
| Scale ruler (metric) | |
| Masking tape |
| S/N | Item | Quantity |
|---|---|---|
| 1 | Drawing board | 1 Pc per Candidate |
| 2 | T-square | 1 Pc per Candidate |
| 3 | Set squares (45° and 30°-60°) | 1 Set per Candidate |
| 4 | Protractor | 1 Pc per Candidate |
| 5 | Compass | 1 Pc per Candidate |
| 6 | Pencils (2H, HB, 2B) | 3 Pcs per Candidate |
| 7 | Eraser | 1 Pc per Candidate |
| 8 | Scale ruler (metric) | 1 Pc per Candidate |
| 9 | Drawing paper A3 size | 2 Sheets per Candidate |
| 10 | Masking tape | 1 Roll per 5 Candidates |
| 11 | Set of reference dimensions and working drawing of the component | 1 Set per Candidate |
| Items to be Evaluated | Marks Available | Marks Obtained | Comments |
|---|---|---|---|
| TASK 1: PREPARATION AND SETTING OUT | |||
| Candidate wears appropriate PPE (e.g. dust coat, safety boots) (Award 1 mark for correct PPE worn) | 1 | ||
| Workstation is cleaned and prepared before starting (Award 1 mark for clean and organized workstation) | 1 | ||
| Tools and materials are assembled and checked for completeness (Award 1 mark for correct tools and materials assembled) | 1 | ||
| Sub-Total | 3 | ||
| TASK 2: DRAWING EXECUTION | |||
| Candidate correctly draws the front view of the component using correct scale (Award 3 marks for accurate and scaled front view) | 3 | ||
| Candidate constructs the oblique pictorial projection at 45° angle (Award 4 marks for correct 45° angle and projection construction) | 4 | ||
| Candidate applies correct dimensions (80mm length, 50mm width, 30mm height) on the drawing (Award 4 marks for all dimensions correctly applied) | 4 | ||
| Drawing lines are neat, continuous, and correctly weighted (visible outlines and hidden lines) (Award 3 marks for neatness and correct line work) | 3 | ||
| Candidate labels the drawing correctly including title block and dimension annotations (Award 2 marks for correct labeling and title block) | 2 | ||
| Sub-Total | 16 | ||
| PRODUCT CHECKLIST | |||
| Final oblique pictorial drawing shows correct proportions and angles with dimensions: length 80mm, width 50mm, height 30mm (Award 10 marks for accuracy of dimensions and correct oblique pictorial representation) | 10 | ||
| Drawing is neat, legible, and complete with all required views and annotations (Award 8 marks for overall presentation quality) | 8 | ||
| Sub-Total | 18 | ||
| GRAND TOTAL | 37 | ||
At the start of this chapter we promised you would be able to:
Tick each one you can genuinely do.
So, are you there yet?
You're competent when you can confidently do 50% or more of what this chapter promised.
Sign in to record how you're doing.