Isometric, orthographic, and exploded drawings communicate different information about a design. Isometric drawings show its three-dimensional form, orthographic drawings specify its shape and dimensions accurately, and exploded drawings explain how its components relate and fit together.
These drawing methods are forms of graphical modelling used during prototyping to communicate, develop, and evaluate design ideas.
| Drawing type | Main characteristics | Main purpose |
|---|---|---|
| Isometric drawing | A single three-dimensional view. Vertical lines remain vertical, while receding lines are normally drawn at 30 degrees to the horizontal. Parallel edges remain parallel rather than converging. | Communicates the overall form, proportions, and appearance of a design clearly. It is useful when presenting an idea to a client or user. |
| Orthographic drawing | A set of separate two-dimensional views, usually front, plan, and side. Views are aligned and may include dimensions, line conventions, scale, and first-angle or third-angle projection symbols. | Provides precise information for manufacturing, measurement, and quality control. Each view shows true shapes and sizes when surfaces are parallel to the viewing plane. |
| Exploded drawing | Components are separated visually but remain positioned along their assembly relationships. Dashed lines or directional indicators may show where parts connect. | Communicates assembly order, component relationships, maintenance, repair, or disassembly. It can be based on an isometric pictorial view. |
A common misconception is that an isometric drawing uses perspective. It does not: parallel lines remain parallel, whereas in a perspective drawing, receding parallel lines appear to converge toward vanishing points. Another mistake is treating an exploded drawing as a random arrangement of parts; the spatial relationship and assembly sequence must remain clear.
For an IB Design Technology response on , identify each drawing by both its visual conventions and purpose. If asked to compare them, state what information each communicates and explain why that information is useful at a particular stage of prototyping, manufacture, assembly, or evaluation.