Orthographic projection

Karibu! Welcome to the World of Technical Drawing!

Habari mwanafunzi! Ready to unlock a superpower? Imagine you could describe a complex object, like a brand new motorbike or even a simple kiti (chair), to a fundi (craftsman) anywhere in Kenya without using a single word, only drawings. That's what orthographic projection allows you to do! It's the language of engineers, architects, and designers. Forget blurry photos; we are going to learn how to represent 3D objects perfectly in 2D. Let's begin this exciting journey!

What on Earth is Orthographic Projection?

That sounds like a complicated phrase, doesn't it? Let's break it down. "Ortho" comes from a Greek word meaning 'right' or 'straight'. "Graphic" means 'drawing'. So, Orthographic Projection is simply a method of making a 'straight drawing' of an object as seen from different angles, always at a perfect 90-degree view.

Think of it like this: Imagine you have a yellow 20-litre jerrycan. To describe it fully, you would need to show:

• What it looks like from the front (where the main flat side is).
• What it looks like from the top (where the cap and handle are).
• What it looks like from the side (the thinner part).

The easiest way to understand this is with the "Glass Box" method. Imagine you place the object inside a transparent glass box. You then look at each face of the box straight-on and trace the outline of the object onto the glass. When you unfold the box, you have your orthographic views!

     _________________________
    /|                       /|
   / |                      / |
  /  |        TOP VIEW      /  |
 /___|_____________________/   |
|    |                     |   |
|    |      +------+       |   |
|    |      |      |       |  /
|    |      | JERRYCAN |       | /  SIDE VIEW
|    |      |      |       |/
|    +------+------+------
|   /                      |
|  /    FRONT VIEW         |
| /                      |
|/_______________________|

Image Suggestion: A clear, photorealistic 3D render of a simple object like a wooden block placed inside a transparent, glowing glass cube. Dotted lines should project from the corners of the block straight out to the surfaces of the cube, forming the 2D shapes on the front, top, and side panels. The style should be clean and educational.

The Principal Views: Your Three Best Friends

In orthographic projection, we focus on three main views, also called 'Principal Views'.

1. The Front View (or Front Elevation): This is the main view. It's the one that shows the most detail about the object. You choose what you consider the "front".
2. The Top View (or Plan): This is what you would see if you were a bird flying directly over the object. You are looking straight down.
3. The Side View (or End Elevation): This is what you see looking at the object from the side (usually the left or right side).

First Angle vs. Third Angle: The Kenyan Standard

Now, how we arrange these drawings on paper is very important. There are two main systems in the world: First Angle and Third Angle Projection. In Kenya, and much of Europe and Asia, we use First Angle Projection.

Here’s the simplest way to remember the layout for First Angle:

• The view from the TOP is drawn at the BOTTOM.
• The view from the LEFT side is drawn on the RIGHT.

It sounds a bit backwards, but think of it like unfolding that glass box. The top flap goes down, and the left flap opens to the right. This is the standard you will use for all your exams and professional work in Kenya!

     FIRST ANGLE PROJECTION LAYOUT
     -----------------------------

      +-----------------+-----------------+
      |                 |                 |
      |   (Side View    |   (Front View)  |
      | from the LEFT)  |                 |
      |                 |                 |
      +-----------------+-----------------+
      |                 |                 |
      |                 |   (Top View)    |
      |                 |                 |
      |                 |                 |
      +-----------------+-----------------+

Image Suggestion: A clean, colourful educational diagram showing the layout of First Angle Projection. It should feature a simple 3D object (like a toy car) in the centre, with arrows pointing to the Front, Top, and Left. Then, show the corresponding 2D views arranged correctly on a drawing sheet, with the Top view below the Front view, and the Left-side view to the right of the Front view. Each view should be clearly labeled.

Let's Draw! A Step-by-Step Guide

Enough theory! Let's get our hands dirty. We will draw a simple L-shaped block. Grab your paper, pencil, T-square, and set squares!

Our Object: The L-Block

          .
         / \
        / _ \
       / / \ \
      / /   \ \
     / /     \ \
    / +-------+ \
   / /|       |/
  / / +-------+
 +-+ /
 | |/
 +-+

Step 1: Draw the Front View

We'll decide the L-shape is most clear from the front. Let's say it is 60mm wide and 50mm high. The thickness is 20mm.

    FRONT VIEW
    (What you see looking from the front)

    50mm  ^
          | +-------+
          | |       | 20mm
          | |       |
          | +-------+-------+
          | |               | 20mm
          | +---------------+
          +----------------->
                60mm

Step 2: Project Upwards for the Top View

Using your T-square and set square, draw very light, thin lines (construction lines) straight up from every corner of your Front View. The Top View will be directly above it (for now, before we move it to the final position).

Step 3: Draw the Top View

Looking down from the top, we would see two rectangles. The width is the same as the front view (60mm), and the depth is, let's say, 30mm. Align it with your projection lines.

    TOP VIEW
    (Aligned with Front View below it)

    +-------+-------+
    |       |       |  30mm
    +-------+-------+
      20mm    40mm
       <------------>
            60mm

Step 4: Project Across for the Side View

Now, from the Front View, project light construction lines horizontally to the right. To get the depth, we use a special trick: draw a 45-degree line. Project lines up from the Top View, hit the 45-degree line, and then project them down. This magically transfers the depth dimension!

However, for First Angle, we will draw the view from the left on the right side. Looking from the left, we'd see a simple rectangle, 50mm high and 30mm deep.

    SIDE VIEW (from the Left)
    (Aligned with Front View to its left)

         ^
         | +---+
         | |   |
    50mm | |   |
         | |   |
         | +---+
         +----->
           30mm

Step 5: Final Layout (First Angle Projection)

Now, let's arrange everything correctly according to the First Angle rules. Clean up your construction lines, and make the object lines bold and clear!

      +---------------------------------+
      |                                 |
      |      FRONT VIEW                 |
      |      +-------+                  |
      |      |       |                  |
      |      |       |      SIDE VIEW   |
      |      +-------+-------+  (Left)  |
      |      |               |  +---+   |
      |      +---------------+  |   |   |
      |                         |   |   |
      |                         |   |   |
      |      TOP VIEW           +---+   |
      |      +-------+-------+          |
      |      |       |       |          |
      |      +-------+-------+          |
      |                                 |
      +---------------------------------+

Why Does This Matter? The Fundi in Lamu

Imagine you are an architect in Nairobi. You have designed a beautiful custom-made window frame for a new hotel being built in Lamu. You can't travel there to explain every little detail to the carpenter (fundi). So what do you do?

You create an orthographic drawing!

• The Front View shows the beautiful patterns and overall shape of the frame.
• The Top View shows how thick the frame is and where the grooves for the glass should be cut.
• The Side View shows the exact profile of the wooden frame.

You email this single piece of paper to the fundi in Lamu. Because he also understands the "language" of orthographic projection, he can build the window frame exactly as you designed it. No confusion, no mistakes. It is a universal language for making things!

Let's Recap!

Wow, you've learned a lot today! Here are the key things to remember:

• Orthographic Projection is a way to draw a 3D object in 2D using multiple "straight-on" views.
• The three main views are the Front View, Top View, and Side View.
• In Kenya, we use the First Angle Projection system. (Top view goes at the bottom, left view goes on the right).
• Always use light projection lines to make sure your views are perfectly aligned. This is the secret to a professional drawing!

Practice is everything in Technical Drawing. Start with simple objects around you: a book, your phone, a box of matches. Try to draw them in First Angle projection. The more you draw, the easier it will become. Hongera, you are on your way to becoming a skilled designer!