Lesson 3.3: Orthographic and Technical Views

Introduction

In art and design, aside from expressive observation, the ability to convey ideas clearly and accurately is essential. The goal of this lesson is to teach you, students, about the conventions of orthographic and technical views. We will cover how to communicate an object or space through multiple views, such as plans, elevations, and sections. By the end of this lesson, you will understand how to create precise drawings that communicate design intent.

Learning Objectives

Understand plans, elevations, and sections as design drawing conventions.
Learn how to communicate an object or space through multiple views.
Grasp the concepts of scale, dimensions, and basic technical annotation.
Identify where technical drawing is applied in various design disciplines.
Produce a clear set of technical views by hand.

What is Orthographic Projection?

Orthographic projection is a method of representing three-dimensional objects in two dimensions. It employs multiple views, typically including the front, top, and side, to ensure all the important features are conveyed with precision. This method does not utilize perspective; rather, it maintains the scale and proportion of the object consistently across all views.

Key Components of Orthographic Views

Front View: This displays the object as it appears when viewed from the front.
Top View: This shows the object from above, providing an overview of its shape and layout.
Side View: This represents the object from the side, allowing for a greater understanding of depth and height.
Sectional Views: These are used to show interior details that are not visible in standard views.

Example of Orthographic Projection

Consider a simple rectangular box. The orthographic views of this box would look like the following:

Front View: A rectangle showing the height and width.
Top View: A rectangle showing the width and depth.
Side View: A rectangle showing the height and depth.

These views can help communicate the dimensions clearly. For example, if the box has a width of $W$, a height of $H$, and a depth of $D$, it can be illustrated in each view by annotating the dimensions.

Worked Example

Imagine we have a box with dimensions:

Width $W = 10 \text{ cm}$
Height $H = 5 \text{ cm}$
Depth $D = 15 \text{ cm}$

Step 1: Draw the Front View

Simply draw a rectangle that is $10 \text{ cm}$ wide and $5 \text{ cm}$ high. Annotate the dimensions as such:

Front View:

+----------+  
|          | 5 cm
|          |  
+----------+  
        10 cm

Step 2: Draw the Top View

Next, draw a rectangle that is $10 \text{ cm}$ wide and $15 \text{ cm}$ deep. Again, annotate:

Top View:

+----------------+  
|                |  
+----------------+  
        10 cm

Step 3: Draw the Side View

Finally, draw a rectangle that is $15 \text{ cm}$ deep and $5 \text{ cm}$ high.

Side View:

+----------+  
|          | 5 cm  
|          |  
+----------+  
        15 cm

Misconceptions About Orthographic Projections

Many students believe that an orthographic projection must look realistic, however, the strength of orthographic drawing lies in its simplicity and clarity. Realism is not the goal; instead, accurate proportions and scales are more critical.

Scale and Dimensions in Technical Drawings

Scale refers to the ratio of the size of the drawing to the actual size of the object. When creating technical drawings, it is crucial to set a scale that allows the viewer to understand the true dimensions of the object with clarity.

How to Choose a Scale

To select an appropriate scale for your drawing, consider the size of the drawing surface. For larger objects, a drawing scale that reduces the object size makes it easier to fit everything on the page.

Common Scales Used:

1:1: Actual size
1:2: Half size
1:10: One-tenth actual size

Example of Creating a Scale Drawing

Assume we intend to draw a chair that measures $80 \text{ cm}$ in height, $45 \text{ cm}$ in width, and $50 \text{ cm}$ in depth. If we decide to use a scale of $1:5, we would compute the dimensions as follows:

Height: $80 \div 5 = 16 \text{ cm}$
Width: $45 \div 5 = 9 \text{ cm}$
Depth: $50 \div 5 = 10 \text{ cm}$

On the drawing, each dimension should be labeled clearly next to the corresponding line or edge to ensure the viewer easily understands the size of the actual object.

Basic Technical Annotation

Annotations are essential in technical drawings. They provide necessary information that is not immediately visible in the views themselves. Basic annotations often include:

Dimensions: Exact measurements in appropriate units.
Labels: Identifying parts of the drawing.
Symbols: Denote specific features such as doors, windows, etc.

Example of Annotations in a Technical Drawing

When you present your chair drawing, it might look like this:

+-------+  
|       | 16 cm  
| Chair |        
|       |  
+-------+  
       9 cm
         
+--+  
|  |       10 cm
+--+

Annotated:

Height of chair: $80 \text{ cm}$
Scale used: $1:5
Width: $45 \text{ cm}$
Depth: $50 \text{ cm}$

Applications of Technical Drawing in Design Disciplines

Technical drawings are used in various design fields including engineering, architecture, and product design. Each discipline has specific requirements, but the principles of orthographic projection remain fairly consistent.

Examples of Applications:

Architecture: Plans and elevations are utilized to convey details about buildings and spaces.
Engineering: Technical drawings are used to specify dimensions, tolerances, and materials required for manufacturing.
Product Design: Detailed technical views help convey the intricacies of a product for production and assembly.

Conclusion

Understanding orthographic and technical views is fundamental for effective communication in art and design. Multiple views help communicate the form, layout, and functional aspects of objects and spaces clearly. Mastery of this skill enables you to articulate your design ideas with precision and professionalism.

Study Notes

Orthographic projection uses multiple views to display 3D objects in 2D.
Front view, top view, and side view are the primary projections used.
Scale is the ratio between the drawing size and actual object size.
Annotations are essential for clarity and detail in technical drawings.
Technical drawings are integral in fields like architecture, engineering, and product design.