Types of Engineering Drawing : Definition, Usage, Diagram

Engineering drawing, also known as technical drawing, is a graphical representation of an object or system that is used by engineers, architects, and designers to communicate their ideas and designs. There are several types of engineering drawings, including:

1. Orthographic drawings.

2. Isometric drawings.

3. Exploded drawings.

4. Perspective drawings.

5. Sectional drawings.

6. Piping and instrumentation diagrams.

7. Schematic diagrams.

1.Orthographic drawings: 

Orthographic drawings, also known as multi view drawings, are 2D representations of an object that show its three main views: front, top, and side. These views are drawn as if they were seen by an observer looking directly at each face of the object. An orthographic drawing, also known as an orthographic projection or engineering drawing, is a type of technical drawing that represents a three-dimensional object in two dimensions. It uses a series of views that show the object from different angles and planes, including top, front, and side views.

Orthographic drawings are commonly used in engineering, architecture, and design to communicate information about an object's size, shape, and features. They are often used in conjunction with other types of technical drawings, such as isometric or perspective drawings.

Example of Orthographic Drawing:

Here's an example of an orthographic drawing:

An orthographic drawing, also known as a technical drawing, is a type of drawing used to represent a three-dimensional object on a two-dimensional plane. It is typically used in engineering, architecture, and other technical fields.

Here is an example of an orthographic drawing of a simple object, a cube:

In this example, the cube is represented in three different views: front, top, and right. The front view shows the front face of the cube, the top view shows the top face of the cube, and the right view shows the right face of the cube. By combining these views, a complete representation of the cube can be created.

2. Isometric drawings: 

Isometric drawings are a type of 3-dimensional drawing that represents an object using a combination of 2D shapes and lines to create a 3D illusion. Isometric drawings are often used in engineering, architecture, and design to show the three-dimensional view of an object in a two-dimensional space.

In isometric drawings, all three axes - x, y, and z - are equally foreshortened, so that the object appears as if it is tilted at a 45-degree angle. This makes it easier to visualize the object's dimensions and relationships between different parts.

Example of Isometric Drawing:

Here is an example of an isometric drawing of a cube:

This is an isometric drawing of a cube. As you can see, it shows the three faces of the cube in a way that accurately represents their relative positions and sizes. Isometric drawings are often used in engineering, architecture, and design to help visualize objects and structures in three dimensions.

3. Exploded drawings: 

An exploded drawing is a visual representation of an object or structure that shows its components separated and positioned relative to each other as if they have been disassembled or exploded apart. It is typically used to illustrate how the parts of a complex object fit together and to aid in the assembly process.

Example of Exploded Drawing:

Another example is the exploded view of a car engine, which shows each component of the engine separated and positioned relative to each other as if they have been disassembled. This type of drawing can be used to illustrate how the different parts of the engine work together and to aid in the repair or assembly process.

4. Perspective drawings: 

Perspective drawings are a type of drawing that creates the illusion of three-dimensional space on a two-dimensional surface. They are used to create realistic and accurate depictions of objects and scenes, and they are commonly used in architecture, product design, and art.

Perspective drawings are created using techniques that simulate the way the human eye perceives depth and distance in the real world. There are several types of perspective drawing, including one-point perspective, two-point perspective, and three-point perspective.

Example of Perspective Drawings:

Here are a few examples of perspective drawings:

• An architectural rendering of a building: This type of perspective drawing is commonly used to visualize the exterior of a building before it is constructed. The drawing shows the building from a three-dimensional perspective, giving the viewer a sense of its height, depth, and scale.
• A product design drawing: Perspective drawings are often used in product design to create realistic and accurate depictions of products before they are manufactured. The drawing shows the product from multiple angles, giving the viewer a sense of its shape, size, and features.
• A landscape drawing: Perspective drawings can also be used to create detailed and realistic depictions of landscapes, cityscapes, and other outdoor scenes. The drawing shows the scene from a three-dimensional perspective, giving the viewer a sense of depth and distance.
• An interior design rendering: Perspective drawings are commonly used in interior design to visualize how a space will look before it is furnished and decorated. The drawing shows the space from a three-dimensional perspective, giving the viewer a sense of the layout, scale, and proportions of the space.
• A character design sketch: Perspective drawings can also be used in art and animation to create detailed and realistic depictions of characters and creatures. The drawing shows the character from multiple angles, giving the viewer a sense of its shape, size, and features from different perspectives.

5. Sectional drawings: 

Sectional drawings, also known as cross-sectional drawings, are a type of technical drawing that shows the internal structure of an object or building. They are created by cutting through an object or building at a specific location and then drawing the resulting exposed surfaces and structures as if they were viewed from that angle.

Sectional drawings are commonly used in architecture, engineering, and product design to provide a detailed understanding of the internal workings of an object or structure. They are typically accompanied by notes and dimensions that provide additional information about the object or structure being depicted.

Example of sectional Drawings:

A sectional drawing is a type of technical drawing that shows an object as if it had been sliced or cut through a plane, revealing its internal structure. Here is an example of a sectional drawing:

This is a sectional drawing of a car engine, showing the various internal components such as the pistons, crankshaft, camshaft, and valves. The section plane is indicated by the diagonal line with arrows on either end. By looking at this drawing, you can get a better understanding of how the engine works and how the different parts interact with each other.

6. Piping and instrumentation diagrams: 

Piping and Instrumentation Diagrams (P&IDs) are detailed diagrams used in industrial settings to illustrate the piping and process flow of a system, as well as the instrumentation and control devices that are used to monitor and control the system.

P&IDs are typically used in the chemical, petrochemical, power generation, and oil and gas industries to show the flow of fluids and gases through a system, as well as the location and function of process equipment such as pumps, heat exchangers, and reactors. They also show the instrumentation and control devices that are used to monitor and regulate the process, such as sensors, controllers, and valves.

Example of Piping and Instrumentation Diagrams Drawings:

Here's an example of a Piping and Instrumentation Diagram (P&ID) drawing:

In this example, the P&ID shows a simple process flow diagram for a water treatment plant. The drawing includes various piping and equipment symbols, such as pumps, tanks, valves, and filters, as well as instrumentation symbols, such as flow meters, level sensors, and pressure gauges.

The piping and instrumentation lines are labeled with letters and numbers to indicate the flow direction and the type of fluid or gas being transported. The drawing also includes notes and labels to provide additional information about the equipment and instrumentation.

Overall, this P&ID drawing provides a detailed and standardized representation of the water treatment process, which is essential for ensuring efficient and safe operation of the plant.

7. Schematic diagrams: 

Schematic diagrams are graphical representations of a system or process that use symbols and lines to illustrate how the system or process operates. They are commonly used in electrical and electronic engineering to illustrate the connections and functions of various components in a circuit or system.

Schematic diagrams use standardized symbols and notation to represent different types of components, such as resistors, capacitors, transistors, and integrated circuits. They also use lines and arrows to show how the components are connected and how signals flow through the system.

Example of  Schematic diagrams Drawings:

Here is an example of a schematic diagram:

In this example, the schematic diagram shows a simple capacitor circuit. The drawing includes symbols for the capacitor, battery, and resistor, as well as lines and arrows to show how the components are connected and how the current flows through the circuit.

The schematic diagram also includes labels and values for the components, such as the voltage of the battery and the capacitance and resistance of the capacitor and resistor, respectively.

Overall, this schematic diagram provides a detailed and standardized representation of the capacitor circuit, which is essential for designing, analyzing, and troubleshooting electrical circuits in a wide range of applications, from electronics to power systems.